EPA AP-42A
COMPILATIC
OF
MR POLLUTANT EMISSION FACTORS
Third Edition
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
August 1977
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This report is published by the Environmental Protection Agency to report information of general interest in the
field of air pollution. Copies are available free of charge to Federal employees, current contractors and grantees,
and nonprofit organizations—as supplies permit—from the Library Services Office, Environmental Protection
Agency, Research Triangle Park, North Carolina 27711. This document is also available to the public for sale
through the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.
Publication No. AP-42
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PREFACE
This document reports data available on those atmospheric emissions for which sufficient
information exists to establish realistic emission factors. The information contained herein is based
rj on Public Health Service Publication 999-AP-42, Compilation of Air Pollutant Emission Factors, by
R.L. Duprey, and on three revised and expanded editions of Compilation of Air Pollutant Emission
Factors that were published by the Environmental Protection Agency in February 1972, April 1973,
and February 1976. This document is the third edition and includes the supplements issued in July
1973, September 1973, July 1974, January 1975, December 1975, April 1976, and April 1977 (see
page iv). It contains no new information not already presented in the previous issuances.
Chapters and sections of this document have been arranged in a format that permits easy and
convenient replacement of material as information reflecting more accurate and refined emission
factors is published and distributed. To speed dissemination of emission information, chapters or
sections that contain new data will be issued—separate from the parent report—whenever they are
revised.
To facilitate the addition of future materials, the punched, loose-leaf format was selected. This
, approach permits the document to be placed in a three-ring binder or to be secured by rings, rivets, or
other fasteners; future supplements or revisions can then be easily inserted. The lower left- or right-
, hand corner of each page of the document bears a notation that indicates the date the information was
f._ issued.
Information on the availability of future supplements to Compilation of Air Pollutant Emission
Factors can be obtained from the Environmental Protection Agency, Library Services, MD-35,
Research Triangle Park, N.C. 27711 (Comm. Telephone: 919-541-2777, FTS: 629-2777).
Comments and suggestions regarding this document should be directed to the attention of
Director, Monitoring and Data Analysis Division, Office of Air Quality Planning and Standards,
Environmental Protection Agency, Research Triangle Park, N.C. 27711.
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ACKNOWLEDGMENTS
Because this document is a product of the efforts of many individuals, it is impossible to acknow-
ledge each person who has contributed. Special recognition is given to Environmental Protection
Agency employees in the Requests and Information Section, National Air Data Branch, Monitoring
and Data Analysis Division, for their efforts in the production of this work. Bylines identify the
contributions of individual authors who revised specific sections and chapters.
IV
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PUBLICATIONS IN SERIES
Issuance
Compilation of Air Pollutant Emission Factors (second edition)
Supplement No. 1
Section 4.3 Storage of Petroleum Products
Section 4.4 Marketing and Transportation of Petroleum Products
Supplement No. 2
Introduction
Section 3.1.1 Average Emission Factors for Highway Vehicles
Section 3.1.2 Light-Duty, Gasoline-Powered Vehicles
1.5
1.6
2.5
7.6
7.11
Supplement No.
Introduction
Section 1.4
Section
Section
Section
Section
Section
Section 10.1
Section 10.2
Section 10.3
Supplement No.
Section 3.2.3
Section 3.2.5
Section 3.2.6
Section 3.2.7
Section 3.2.8
Section 3.3.1
Section 3.3.3
Chapter 11
Appendix B
Appendix C
Supplement No.
Section 1.7
Section 3.1.1
Section 3.1.2
Section 3.1.3
Section 3.1.4
Section 3.1.5
Section 5.6
Section 11.2 '
Appendix C
Appendix D
Release Date
4/73
7/73
9/73
7/74
Natural Gas Combustion
Liquified Petroleum Gas Combustion
Wood/Bark Waste Combustion in Boilers
Sewage Sludge Incineration
Lead Smelting
Secondary Lead Smelting
Chemical Wood Pulping
Pulpboard
Plywood Veneer and Layout Operations
Inboard-Powered Vessels
Small, General Utility Engines
Agricultural Equipment
Heavy-Duty Construction Equipment
Snowmobiles
Stationary Gas Turbines for Electric Utility Power Plants
Gasoline and Diesel Industrial Engines
Miscellaneous Sources
Emission Factors and New Source Performance Standards
NEDS Source Classification Codes and Emission Factor Listing
Lignite Combustion
Average Emission Factors for Highway Vehicles
Light-Duty, Gasoline-Powered Vehicles (Automobiles)
Light-Duty, Diesel-Powered Vehicles
Light-Duty, Gasoline-Powered Trucks and Heavy-Duty, Gasoline-Powered Vehicles
Heavy-Duty, Diesel-Powered Vehicles
Explosives
Fugitive Dust Sources
NEDS Source Classification Codes and Emission Factor Listing
Projected Emission Factors for Highway Vehicles
1/75
12/75
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Supplement No. 6
Section 1.3
Section 2.4
Section 3.3-2
Section 6.1
Section 6.12
Section 9.2
Section 10.4
Supplement to No.
Section 1.2
Section 1.3
Section 1.5
Section 1.8
Section 1.9
Section 2.4
Section 4.1
Section 4.3
Section 4.4
Section 5.1
Section 5.3
Section 5.4
Section 5.12
Section 6.4
Section 6.6
Section 8.6
Section 8.15
Section 10.1.3
Appendix B
Issuance
Fuel Oil Combustion
Open Burning
Heavy-Duty, Natural-Gas-Fired Pipeline Compressor Engines
Alfalfa Dehydrating
Sugar Cane Processing
Natural Gas Processing
Woodworking Operations
Anthracite Coal Combustion
Fuel Oil Combustion
Liquefied Petroleum Gas Combustion
Bagasse Combustion in Sugar Mills
Residential Fireplaces
Open Burning
Dry Cleaning
Storage of Petroleum Liquids
Transportation and Marketing of Petroleum Liquids
Adipic Acid
Carbon Black
Charcoal
Phthalic Anhydride
Feed and Grain Mills and Elevators
Fish Processing
Portland Cement Manufacturing
Lime Manufacturing
Acid Sulfite Pulping
Emission Factors and New Source Performance Standards
Release Date
4/76
4/77
VI
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CONTENTS
Page
LIST OF TABLES xvii
LIST OF FIGURES xxi
ABSTRACT xxiii
INTRODUCTION 1
1. EXTERNAL COMBUSTION SOURCES 1
1.1 BITUMINOUS COAL COMBUSTION
I.I.I General
1.1.2 Emissions and Controls
References for Section 1.1
ANTHRACITE COAL COMBUSTION
1.2.1 General
1.2.2 Emissions and Controls
References for Section 1.2 . . .
1.3 FUEL OIL COMBUSTION
1.3.1 General
1.3.2 Emissions
1.3.3 Controls
References for Section 1.3
1.4 N ATURAL GAS COMBUSTION
1.4.1 General
1.4.2 Emissions and Controls
References for Section 1.4
1.5 LIQUEFIED PETROLEUM GAS COMBUSTION
I.S.I General .
1.5.2 Emissions
References for Section 1.5
1.6 WOOD WASTE COMBUSTION IN BOILERS
1.6.1 General . . . .
1.6.2 Firing Practices
1.6.3 Emissions . . .
References for Section 1 .6
1.7 LIGNITE COMBUSTION
1.7.1 General
1.7.2 Emissions and Controls
References for Section 1.7
-4
.2-4
.3-1
.3-1
.3-1
.3-3
.3-4
.4-1
.4-1
.4-1
.4-3
.5-1
.5-1
.5-1
.5-1
.6-1
.6-1
.6-1
.6-1
.6-2
.7-1
.7-1
.7-1
.7-2
1.8 BAGASSE COMBUSTION IN SUGAR MILLS 1.8-1
1.8.1 General 1.8-1
1.8.2 Emissions and Controls 1.8-1
Reference for Section 1.8 1.8-2
1.9 RESIDENTIAL FIREPLACES 1.9-1
1.9.1 General 1.9-1
1.9.2 Emissions 1.9-1
References for Section 1.9 1.9-2
2. ^OLID WASTE DISPOSAL 2.I-I
2.1 REFUSE INCINERATION 2.1-2
2.1.1 Process Description t 2.1-2
2.1.2 Definitions of Incinerator Categories 2.1-2
2.1.3 Emissions and Controls 2.1-4
Refeiences for Section 2.1 2.1-5
vii
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CONTENTS -- {Continued)
Page
2 2 AUTOMOBILE- BODY INC1NFRATION 2.2-1
22.1 Process Description . , 2.2-1
2 2,2 Emissions and Controls , 2.2-i
References toi ScUuvi 2.2 2.2-2
2 '• CONICAL Bl'RNl RS . 2.3-1
3 .i.l Process Dc''Ciiptioi; . . . 2.3-1
2.3.2 Fmissions am! Con(.">is , , 2.3-1
KetVuiicvs !•>! Section 23. 23-3
; I OPl N BURNING . - . . . , . 2.4-1
It.: ik;.u.il - 2.4-1
2.4.2 rn-svon, 2.4-1
References for Section 2.4 . . . . 2.4-4
2 ^ SEWAGE SLUDGh INCINLRATION 2.5-1
2.5.1 Process Description 2.5-1
2.5.2 ^missions and Controls • ,. . . 2.5-1
References ior Section 2,5 2.5-2
INTERNAL COMBUSTION ENGINE SOURCES „. . . 3.1.1-1
PEHN1TIONS USED IN CFIAPTER 3 • . . 3.1.1-1
3.1 HIGHWAY VEHICLES 3.1.1-2
31.1 Average Emission Factors for Highway Vehicles 3.1.1-3
3.1.2 Light-Duty, Gasoline-Powered Vehicles I Automobiles) 3.1.2-1
3.1.3 Light-Duty, Diesel-Powered Vehicles 3,
3.1.4 Light-Duty, Gasoline-Powered Trucks and Heavy-Duty, Gasoline-Powered Vehicles .... 3.
3.1.5 Heavy-Duty, Diesel-Poweied Vehicles 3.
3.1.6 Gaseous-Fueled Vehicles , 3.
3.1.7 Motorcycles ....... . . .................................... 3.
.3-1
.4-1
.5-1
.6-1
.7-1
3.2 OFF-HIGHWAY, MOBILE SOURCES ................................. 3.2.1-1
3.2.1 Aircraft .................. ...... ..................... 3.2.1-1
3.2.2 Locomotives ............................... . ........... 3.2.2-1
3 2.3 Inboard-Powered Vessels .................................... 3.2.3-1
3.2.4 Outboard-Powered Vessels .................................... 3.2.4-
3.2.5 Small, Genera! Utility Engines ............... '. ................ 3.2.5-
3,2.6 Xgrxultural Equipment ......... ..... ....................... 3.2.6-
3.2.7 Heavy-Duty Construction Equipment .............................. 3.2.7-
3.2.8 Snowmobiles ............... . ............................ 3.2.8-
3.3 OFF-HIGHWAY STATIONARY SOURCES .............................. 3.3.1-
3.3.1 Stationary Gas Turbines for Electric Utility Power Plants .................. 3.3.1-
3.3.2 Heavy-Duty. Natural-Gas-Fired Pipeline Compressor Engines .................. 3.3.2-
3.3.3 Gasoline and Diesel Industrial Engines ............................. 3.3.3-
I. EVAPORATION LOSS SOURCES ...................................... 4.1-
4.1 DRY CLEANING ............................................. 4.1-
4.1.1 General ............. . ...... . .......................... 4.1-1
4.1.2 Emissions and Controls ............................ . ....... 4.1-3
References for Section 4.1 .................................... 4.1-4
4.2 SURFACE COATING ......................................... . . 4.2-1
4.2.1 Process Description ............................... ........ 4.2-1
4/2.2 Emissions and Coni i ok ...................................... 4.2-1
References for .Section 4.2 .................................... 4.2-2
4.3 STORAGE OF PETROLEUM LIQUIDS ... .............................. 4.3-1
4.3.1 Process Description ......................................... 4.3-1
4.3.1.1 Fixed Roof Tanks ..................................... 4.3-1
4.3.1.2 Floating Roof Tanks ............ . ...................... 4.3-1
4.3.1.3 Variable Vapor Space Tanks ............................... 4.3-4
4.3.1.4 Pressure Tanks ....................................... 4.3-5
viii
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CONTENTS - (Continued)
IV
4.3.2 Emissions and Controls 4.3-5
4.3.2.1 Fixed Roof Tanks 4.3-6
4.3.2.2 Floating Roof Tanks 43-12
4.3.2.3 Variable Vapor Space Systems 4.3-13
4.3.2.4 Pressure Tanks 4.3 14
4.3.3 Emission Factors 4.3-14
4.3.3.1 Sample Calculation 4,3-16
References for Section 4.3 • 4.3-17
4.4 TRANSPORTATION AND MARKETING OF PETROLEUM LIQUIDS 4.4-1
4.4.1 Process Description 4.4-1
4.4.2 Emissions and Controls 44-1
4.4.2.1 Large Storage Tanks 4,4 i
4.4.2.2 Marine Vessels, Tank Cars, and Tanktrucks 4.4-1
4.4.2.3 Sample Calculation 4.4-8
4.4.2.4 Service Stations 4.4-10
4.4.2.5 Motor Vehicle Refueling 4.4-11
References for Section 4.4 44-12
5. CHEMICAL PROCESS INDUSTRY . . . 5.i 1
5.1 ADIPICACID 5.1-1
5.1.1 General 5.1-!
5.1.2 Emissions and Controls 5.1-2
References for Section 5.1 5.1-4
5.2 AMMONIA 5.2-1
5.2.1 Process Description 5.2-1
5.2.2 Emissions and Controls .... 5.2-1
References for Section 5.2 5.2-2
CARBON BLACK 5.3-1
5.3.1 Process Description .... 5.3-1
5.3.1.1 Furnace Process , 5.3-1
5.3.1.2 Thermal Process 5.3-1
5.3.1.3 Channel Process 5.33
5.3.2 Emissions and Controls , 5.3-3
References for Section 5.3 5.3-5
j.4 CHARCOAL 5.4-1
5.4.1 Process Description . 5 4.1
5.4.2 Emissions and Controls 5.4-}
References for Section 5.4 5 4-i
5.5 CHLOR-ALKALI 5.5-i
5.5.1 Process Description , .... 5.5.}
5.5.2 Emissions and Controls i .... S.S-!
References for Section 5.5 .5.5-1
5.6 EXPLOSIVES 5.6-1
5.6.1 General 5.6-
5.6.2 TNT Production 5.6-
5.6.3 Nitrocellulose Production 5.6-
5.6.4 Emissions 5.6-
References for Section 5.6 5.6-
5.7 HYDROCHLORIC ACID 5.7-
5.7.1 Process Description 5.7-
5.7.2 Emissions, 5.7 l
References for Section 5.7 5.7-1
5.8 HYDROFLUORIC ACID 5.8-1
5.8.1 Process Description 5.8-1
ix
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CONTENTS - (Continued)
Page
5.8.2 Emissions and Controls 5.8-1
References for Section 5.8 5.8-2
5.9 NITRIC ACID 5.9-1
5.9.1 Process Description 5.9-1
5.9.1.1 Weak Acid Production 5.9-1
5.9.1.2 High-Strength Acid Production 5.9-1
5.9.2 Emissions and Controls 5.9.3
References for Section 5.9 5.9-4
ys.10 PAINT AND VARNISH 5.10-1
5.10.1 Paint Manufacturing 5.10-1 ' *
5.10.2 Varnish Manufacturing 5.10-1
References for Section 5.10 5.10-2
5.11 PHOSPHORIC ACID 5.10-2 *
5.11.1 WetProcess 5.11-1
5.11.2 Thermal Process 5.11-1
References for Section 5.11 5.11-2
5.12 PHTHALIC ANHYDRIDE 5.12-1 '
5.12.1 General 5.12-1
5.12.2 Emissions and Controls 5.12-2
Reference for Section 5.12 5.12-5
./5.13 PLASTICS 5.13-1
5.13.1 Process Description 5.13-1
5.13.2 Emissions and Controls 5.13-1
References for Section 5.13 5.13-2
-/5.14 PRINTING INK 5.14-1
5.14.1 Process Description 5.14-1
5.14.2 Emissions and Controls 5.14-2
References for Section 5.14 5.14-2
y 5.15 SOAP AND DETERGENTS 5.15-1
5.15.1 Soap Manufacture 5.15-1
5.15.2 Detergent Manufacture 5.15-1
References for Section 5.15 5.15-2
5.16 SODIUM CARBONATE 5.16-1
5.16.1 Process Description 5.16-1
5.16.2 Emissions 5.16-1
References for Section 5.16 5.16-2
5.17 SULFURICACID 5.17-1
5.17.1 Process Description 5.17-1
5.17.1.1 Elemental Sulfur-Burning Plants 5.17-1
5.17.1.2 Spent-Acid and Hydrogen Sulfide Burning Plants 5.174
5.17.1.3 Sulfide Ores and Smelter Gas Plants 5.174
5.17.2 Emissions and Controls 5.174
5.17.2.1 Sulfur Dioxide 5.174 »
5.17.2.2 Acid Mist 5.17-5
References for Section 5.17 5.17-8
5.18 SULFUR 5.18-1
5.18.1 Process Description 5.18-1
5.18.2 Emissions and Controls 5.18-1
References for Section 5.18 5.18-2
5.19 SYNTHETIC FIBERS 5.19-1
5.19.1 Process Description 5.19-1
5.19.2 Emissions and Controls 5.19-1
References for Section 5.19 5.19-2
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CONTENTS-(Continued)
Page
SYNTHETIC RUBBER _• • • ; 5'20'1
5.20.1 Process Description '...'. 5.20-1
5.20.2 Emissions and Controls 5.20-1
References for Section 5.20 5.20-2
5.21 TEREPHTHALIC ACID 5 -21'1
5.21.1 Process Description 5.21-1
5.21.2 Emissions 5-21"1
References for Section 5.21 5.2\-l
6. FOOD AND AGRICULTURAL INDUSTRY 6.1-1
6.1 ALFALFA DEHYDRATING 6.1-1
6.1.1 General 6.1-1
6.1.2 Emissions and Controls 6.1-1
References for Section 6.1 6.1-
6.2 COFFEE ROASTING 6.1
6.2.1 Process Description 6.2-1
6.2.2 Emissions 6.2-1
References for Section 6.2 6.2-2
6.3 COTTON GINNING 6.3-1
6.3.1 General 6.3-1
6.3.2 Emissions and Controls 6.3-1
References for Section 6.3 6.3-1
6.4 FEED AND GRAIN MILLS AND ELEVATORS 6.4-1
6.4.1 General 6.4-1
6.4.2 Emissions and Controls 6.4-1
6.4.2.1 Grain Elevators 6.4-1
6.4.2.2 Grain Processing Operations 6.4-3
References for Section 6.4 6.4-6
6.5 FERMENTATION 6.5-1
6.5.1 Process Description 6.5-1
6.5.2 Emissions 6.5-1
References for Section 6.5 6.5-2
6.6 FISH PROCESSING 6.6-1
6.6.1 Process Description 6.6-1
6.6.2 Emissions and Controls 6.6-1
References for Section 6.6 6.6-3
6.7 MEAT SMOKEHOUSES 6.7-1
6.7.1 Process Description 6.7-1
6.7.2 Emissions and Controls 6.7-1
References for Section 6.7 . 6.7-2
6.8 NITRATE FERTILIZERS 6.8-1
6.8.1 General 6.8-1
6.8.2 Emissions and Controls 6.8-1
References for Section 6.8 6.8-2
6.9 ORCHARD HEATERS 6.9-1
6.9.1 General 6.9-1
6.9.2 Emissions 6.9-1
References for Section 6.9 6.9-4
6.10 PHOSPHATE FERTILIZERS 6.10-1
6.10.1 Normal Superphosphate 6.10-1
6.10.1.1 General 6.10-1
6.10.1.2 Emissions 6.10-2
6.10.2 Triple Superphosphate 6.10-2
XI
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CONTENTS - (Continued)
Page
6.10.2.1 General 6.10-2
6.10.2.2 Emissions 6.10-2
6.10.3 Ammonium Phosphate 6.10-2
6.10.3.1 General 6.10-2
6.10.3.2 Emissions 6.10-3
References for Section 6.10 6.10-3
6.11 STARCH MANUFACTURING 6.11-1
6.11.1 Process Description 6.11-1
6.11.2 Emissions 6.11-1
References for Section 6.11 6.11-1
6.12 SUGAR CANE PROCESSING 6.12-1
6.12.1 General 6.12-1
6.12.2 Emissions 6.12-1
References for Section 6.12 6.12-1
'. METALLURGICAL INDUSTRY 7.1-1
7.1 PRIMARY ALUMINUM PRODUCTION 7.1-1
7.1.1 Process Description 7.1-1
7.1.2 Emissions and Controls 7.1-2
References for Section 7.1 7.1-8
7.2 METALLURGICAL COKE MANUFACTURING 7.2-1
7.2.1 Process Description 7.2-1
7.2.2 Emissions 7.2-1
References for Section 7.2 7.2-3
7.3 COPPER SMELTERS 7.3-1
7.3.1 Process Description 7.3-1
7.3.2 Emissions and Controls 7.3-1
References for Section 7.3 7.3-2
7.4 FERROALLOY PRODUCTION 7.4-1
7.4.1 Process Description 7.4-1
7.4.2 Emissions 7.4-1
References for Section 7.4 7.4-2
7.5 IRON AND STEEL MILLS 7.5-1
7.5.1 General 7.5-1
7.5.1.1 Pig Iron Manufacture 7.5-1
7,5.1.2 Steel-Making Processes 7.5-1
7.5.1.3 Scarfing 7.5-1
References for Section 7.5 7.5-6
7.6 LEAD SMELTING 7.6-1
7.6.1 Process Description 7.6-1
7.6.2 Emissions and Controls 7.6-3
References for Section 7.6 7.6-5
7.7 ZINC SMELTING . 7.7-1
7.7.1 Process Description 7.7-1
7.7.2 Emissions and Controls 7.7-1
References for Section 7.7 7.7-2
7.8 SECONDARY ALUMINUM OPERATIONS 7.8-1
7.8.1 Process Description 7.8-
7.8.2 Emissions 7.8-
References for Section 7.8 7.8-2
7.9 BRASS AND BRONZE INGOTS 7.9-
7.9.1 Process Description 7.9-
7.9.2 Emissions and Controls 7.9-
References for Section 7.9 7.9-2
xii
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CONTENTS-(Continued)
Page
7.10 GRAY IRON FOUNDRY 7,10-1
7.10.1 Process Description 7.10-1
7.10.2 Emissions 7.10-1
References for Section 7.10 7.10-2
7.11 SECONDARY LEAD SMELTING 7.11-1
7.11.1 Process Description 7.11-1
7.11.2 Emissions and Controls 7.11-1
References for Section 7.11 7.11-1
7.12 SECONDARY MAGNESIUM SMELTING 7.12-1
7.12.1 Process Description 7.12-1
7.12.2 Emissions 7.12-1
References for Section 7.12 7.12-2
7.13 STEEL FOUNDRIES 7.13-1
7.13.1 Process Description 7.13-1
7.13.2 Emissions 7.13-1
References for Section 7.13 7.13-3
7.14 SECONDARY ZINC PROCESSING 7.14-1
7.14.1 Process Description 7.14-1
7.14.2 Emissions 7.14-1
References for Section 7.14 7.14-2
MINERAL PRODUCTS INDUSTRY 8.1-1
8.1 ASPHALTIC CONCRETE PLANTS 8.1-1
8.1.1 Process Description 8.1-1
8.1.2 Emissions and Controls 8.1-4
References for Section 8.1 8.1-5
8.2 ASPHALT ROOFING 8.2-1
8.2.1 Process Description 8.2-1
8.2.2 Emissions and Controls 8.2-1
References for Section 8.2 8.2-2
8.3 BRICKS AND RELATED CLAY PRODUCTS 8.3-1
8.3.1 Process Description 8.3-1
8.3.2 Emissions and Controls 8.3-1
References for Section 8.3 8.3-4
8.4 CALCIUM CARBIDE MANUFACTURING 8.4-1
8.4.1 Process Description 8.4-1
8.4.2 Emissions and Controls 8.4-1
References for Section 8.4 8.4-2
8.5 CASTABLE REFRACTORIES 8.5-1
8.5.1 Process Description 8.5-1
8.5.2 Emissions and Controls 8.5-1
References for Section 8.5 8-5-2
8.6 PORTLAND CEMENT MANUFACTURING 8.6-1
8.6.1 Process Description 8.6-1
8.6.2 Emissions and Controls 8.6-1
References for Section 8.6 8.6-2
8.7 CERAMIC CLAY MANUFACTURING 8.7-1
8.7.1 Process Description 8.7-1
8.7.2 Emissions and Controls , . . . 8.7-1
References for Section 8.7 8.7-2
8.8 CLAY AND FLY-ASH SINTERING 8.8-1
8.8.1 Process Description 8.8-1
8.8.2 Emissions and Controls 8.8-1
References for Section 8.8 8.8-2
xiii
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CONTENTS~(Continued)
Page
8.9 COAL CLEANING 8.9-1
8.9.1 Process Description 8.9-1
8.9.2 Emissions and Controls 8.9-1
References for Section 8.9 8.9-2
8.10 CONCRETE BATCHING 8'.10-1
8.10.1 Process Description 8.10-1
8.10.2 Emissions and Controls 8.10-1
References for Section 8.10 8.10-2
8.11 FIBER GLASS MANUFACTURING 8.11-1
8.11.1 Process Description " 8.11-1
8.11.1.1 Textile Products 8.11-1
8.11.1.2 Wool Products 8.11-1
8.11.2 Emissions and Controls 8.11-1
References for Section 8.11 8.11-4
8.12 FRIT MANUFACTURING 8.12-1
8.12.1 Process Description 8.12-1
8.12.2 Emissions and Controls 8.12-1
References for Section 8.12 8.12-2
8.13 GLASS MANUFACTURING 8.13-1
8.13.1 Process Description 8.13-1
8.13.2 Emissions and Controls 8.13-1
References for Section 8.13 8.13-2
8.14 GYPSUM MANUFACTURING : 8.14-1
8.14.1 Process Description 8.14-1
8.14.2 Emissions 8.14-1
References for Section 8.14 8.14-2
8.15 LIME MANUFACTURING 8.15-1
8.15.1 General 8.15-1
8.15.2 Emissions and Controls 8.15-3
References for Section 8.15 8 15.5
8.16 MINERAL WOOL MANUFACTURING 8.16-1
8.16.1 Process Description 8.16-1
8.16.2 Emissions and Controls 8.16-1
References for Section 8.16 8.16-2
8.17 PERLITE MANUFACTURING 8.17-1
8.17.1 Process Description 8.17-1
8.17.2 Emissions and Controls 8.17-1
References for Section 8.17 8.17-2
8.18 PHOSPHATE ROCK PROCESSING 8.18-1
8.18.1 Process Description 8.18-1
8.18.2 Emissions and Controls 8.18-1
References for Section 8.18 8.18-2
8.19 SAND AND GRAVEL PROCESSING 8.19-1
8.19.1 Process Description 8.19-1
8.19.2 Emissions 8.19-1
References for Section 8.19 8.19-1
8.20 STONE QUARRYING AND PROCESSING 8.20-1
8.20.1 Process Description 8.20-1
8.20.2 Emissions 8.20-1
References for Section 8.20 8.20-2
9. y PETROLEUM INDUSTRY 9.1-1
9.1 PETROLEUM REFINING 9.1-1
9.1.1 General 9.M
xiv
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CONTENTS-(Continued)
9.1.2 Crude Oil Distillation 9.1-1
9.1.2.1 Emissions 9.1-1
9.1.3 Converting 9.1-6
9.1.3.1 Catalytic Cracking 9.1-6
9.1.3.2 Hydrocracking 9.1-6
9.1.3.3 Catalytic Reforming 9.1-6
9.1.3.4 Polymerization, Alkylation, and Isomerization 9,1-6
9.1.3.5 Emissions 9.1-7
9.1.4 Treating 9.1-7
9.1.4.1 Hydrogen Treating 9.1.7
9.1.4.2 Chemical Treating 9.1-7
9.1.4.3 Physical Treating 9.1-8
9.1.4.4 Emissions 9.1-8
9.1.5 Blending 9.1-8
9.1.5.1 Emissions 9.1-8
9.1.6 Miscellaneous Operations 9.1-8
References for Chapter 9 . 9.1-8
9.2 NATURAL GAS PROCESSING 9.2-
9.2.1 General 9.2-
9.2-2 Process Description 9.2-
9.2-3 Emissions 9.2-
References for Section 9.2 9.2-5
10. WOOD PROCESSING 10.1-
10.1 CHEMICAL WOOD PULPING 10.1-
10.1.1 General 10.1-1
10.1.2 Kraft Pulping 10.1-1
10.1.3 Acid Sulfite Pulping 10.1-4
10.1.3.1 Process Description 10.1-4
10.1.3.2 Emissions and Controls 10.1-7
10.1.4 Neutral Sulfite Semichemical (NSSC) Pulping 10.1-?
10.1.4.1 Process Description 10.1-7
10.1.4.2 Emissions and Controls 10.1-9
References for Section 10.1 10.1-9
10.2 PULPBOARD 10.2-1
10.2.1 General 10.2-1
10.2.2 Process Description 10.2-1
10.2.3 Emissions 10.2-1
References for Section 10.2 10.2-1
10.3 PLYWOOD VENEER AND LAYOUT OPERATIONS 10.3-1
10.3.1 Process Descriptions 10.3-1
10.3.2 Emissions 10.3-2
References for Section 10.3 10.3-2
10.4 WOODWORKING OPERATIONS 10.4-1
10.4.1 General 10.4-1
10.4.2 Emissions 10.4-1
References for Section 10.4 10.4-2
II. MISCELLANEOUS SOURCES 11.1-1
11.1 FOREST WILDFIRES 11.1-1
11.1.1 General 11.1-1
11.1.2 Emissions and Controls 11.1-2
xv
-------
CONTENTS - (Continued)
1 i ' FI 'GITIVE DUST SOURCES ........................................ ] 1 : 1
11 2.1 Unpaved Roads (Dirt and Gravel) .............................. '. . . . 11.2 \
1 1 .2.2 Agricultural Tilling ........................................ 112.:-!
1 1 .2.3 Aggregate Storage Piles ...................... ' ......... . ...... 1 1 .' 3-}
1 1 2.4 Heavy Construction Operations ..................................... 1124-1
APPENDIX A. MISCELLANEOUS DATA ..................................... A-1
APPENDIX B. EMISSION FACTORS AND NEW SOURCE PERFORMANCE STANDARDS
FOR STATIONARY SOURCES .............................. .... B-l
APPENDIX C. NEDS SOURCE CLASSIFICATION CODES AND EMISSION FACTOR LISTING ..... C 1
APPENDIX D. PROJECTED EMISSION FACTORS FOR HIGHWAY VEHICLES .......... HI
xvi
-------
LIST OF TABLES-(Continucd)
Table Page
3.1.4-7 Particulate and Sulfur Oxides Emission Factors Light-Duty, Gasoline-Powered Trucks 3.1.4-6
3.1.4-8 Exhaust Emission Factors for Heavy-Duty, Gasoline-Powered Trucks for Calendar Year 1972 ... 3.1.4-7
3.1.4-9 Sample Calculation of Fraction of Gasoline-Powered, Heavy-Duty Vehicle Annual Travel by Model
Year 3.1.4-8
3.1.4-10 Speed Correction Factors for Heavy-Duty Vehicles 3.1.4-9
3.1.4-11 Low Average Speed Correction Factors for Heavy-Duty Vehicles 3.1.4-10
3.1.4-12 Crankcase and Evaporative Hydrocarbon Emission Factors for Heavy-Duty, Gasoline-Powered
Vehicles 3.1.4-10
3.1.4-13 Particulate and Sulfur Oxides Emission Factors for Heavy-Duty Gasoline-Powered Vehicles 3.1.4-11
3.1.5-1 Emission Factors for Heavy-Duty, Diesel-Powered Vehicles (All Pre-1973 Model Years) for
Calendar Year 1972 3.1.5-2 g
3.1.5-2 Emission Factors for Heavy-Duty, Diesel-Powered Vehicles under Different Operating Conditions . 3.1.5-3
3.1.6-1 Emission Factors by Model Year for Light-Duty Vehicles Using LPG, LPG/Dual Fuel, or
CNG/Dual Fuel - . . 3.1.6-2 '
3.1.6-2 Emission Factors for Heavy-Duty Vehicles Using LPG or CNG/Duel Fuel 3.1.6-2 *
3.1.7-1 Emission Factors for Motorcycles 3.1.7-2
3.2.1-1 Aircraft Classification 3.2.1-2
3.2.1-2 Typical Time in Mode for Landing-Takeoff Cycle 3.2.1-3
3.2.1-3 Emission Factors per Aircraft Landing-Takeoff Cycle 3.2.1-4
3.2.14 Modal Emission Factors 3.2.1-6
3.2.2-1 Average Locomotive Emission Factors Based on Nationwide Statistics 3.2.2-1
3.2.2-2 Emission Factors by Locomotive Engine Category , 3.2.2-2
3.2.3-1 Average Emission Factors for Commercial Motorships by Waterway Classification 3.2.3-2
3.2.3-2 Emission Factors for Commercial Steamships-All Geographic Areas 3.2.3-3
3.2.3-3 Diesel Vessel Emission Factors by Operating Mode 3.2.3-4
3.2.3-4 Average Emission Factors for Diesel-Powered Electrical Generators in Vessels 3.2.3-5
3.2.3-5 Average Emission Factors for Inboard Pleasure Craft 3.2.3-6
3.2.4-1 Average Emission Factors for Outboard Motors 3.2.4-1
3.2.5-1 Emission Factors for Small, General Utility Engines 3.2.5-2
3.2.6-1 Service Characteristics of Farm Equipment (Other than Tractors) 3.2.6-1
3.2.6-2 Emission Factors for Wheeled Farm Tractors and Non-Tractor Agricultural Equipment 3.2.6-2
3.2.7-1 Emission Factors for Heavy-Duty, Diesel-Powered Construction Equipment 3.2.7-2
3.2.7-2 Emission Factors for Heavy-Duty, Gasoline-Powered Construction Equipment 3.2.74
3.2.8-1 Emission Factors for Snowmobiles 3.2.8-2
3.3.1-1 Typical Operating Cycle for Electric Utility Turbines 3.3.1-2
3.3.1-2 Composite Emission Factors for 1971 Population of Electric Utility Turbines 3.3.1-2
3.3.2-1 Emission Factors for Heavy-Duty, Natural-Gas-Fired Pipeline Compressor Engines 3.3.2-2
3.3.3-1 Emission Factors for Gasoline-and Diesel-Powered Industrial Equipment 3.3.3-1
4.1-1 Solvent Loss Emission Factors for Dry Cleaning Operations 4.1-4
4.2-1 Gaseous Hydrocarbon Emission Factors for Surface-Coating Applications 4.2-1
4.3-1 Physical Properties of Hydrocarbons 4.3-7
4.3-2 Paint Factors for Fixed Roof Tanks 4.3-10
4.3-3 Tank, Type, Seal, and Paint Factors for Floating Roof Tanks 4.3-13
4.3-4 Evaporative Emission Factors for Storage Tanks 4,3-15
4.4-1 S Factors for Calculating Petroleum Loading Losses 4.4-6
4.4-2 Hydrocarbon Emission Factors for Gasoline Loading Operations , 4.4-7
4.4-3 Hydrocarbon Emission Factors for Petroleum Liquid Transportation and Marketing Sources .... 4.4-8
4.4-4 Hydrocarbon Emissions from Gasoline Service Station Operations 4.4-11
5.1-1 Emission Factors for Adipic Acid Manufacture 5.1-4
xviii
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LIST OF TABLES -(Continued)
Table
5.2-1 Emission Factors for Ammonia Manufacturing without Control Equipment
5.3-1 Emission Factors for Carbon Black Manufacturing
5.4-1 Emission Factors for Charcoal Manufacturing
5.5-1 Emission Factors for Chlor-Alkali Plants
5.6-1 Emission Factors for Explosives Manufacturing
5.7-1 Emission Factors for Hydrochloric Acid Manufacturing
5.8-1 Emission Factors for Hydrofluoric Acid Manufacturing
5.9-1 Nitrogen Oxide Emissions from Nitric Acid Plants
5.10-1 Emission Factors for Paint and Varnish Manufacturing without Control Equipment . ,
5.11-1 Emission Factors for Phosphoric Acid Production
5.12-1 Emission Factors for Phthalic Anhydride
5.13-1 Emission Factors for Plastics Manufacturing without Controls
5.14-1 Emission Factors for Printing Ink Manufacturing
5.15-1 Particulate Emission Factors for Spray-Drying Detergents
5.16-1 Emission Factors for Soda-Ash Plants without Control . . .'
5.17-1 Emission Factors for Sulfuric Acid Plants
5.17-2 Acid Mist Emission Factors for Sulfuric Acid Plants without Controls
5.17-3 Collection Efficiency and Emissions Comparison of Typical Electrostatic Precipitator and Fiber
Mist Eliminator
5.18-1 Emission Factors for Modified Claus Sulfur Plants
5.19-1 Emission Factors for Synthetic Fibers Manufacturing
5.20-1 Emission Factors for Synthetic Rubber Plants: Butadiene-Acrylonitrile and Butadiene.-Styrene
5.21-1 Nitrogen Oxides Emission Factors for Terephthalic Acid Plants
6.1-1 Particulate Emission Factors for Alfalfa Dehydrating Plants
6.2-1 Emission Factors for Coffee Roasting Processes without Controls
6.3-1 Emission Factors for Cotton Ginning Operations without Controls
6.4-1 Particulate Emission Factors for Uncontrolled Grain Elevators
6.4-2 Particulate Emission Factors for Grain Elevators Based on Amount of Grain Received
or Shipped
6.4-3 Particulate Emission Factors for Grain Processing Operations
6.5-1 Emission Factors for Fermentation Processes
6.6-1 Emission Factors for Fish Processing Plants
6.7-1 Emission Factors for Meat Smoking
6.8-1 Emission Factors for Nitrate Fertilizer Manufacturing without Controls
6.9-1 Emission Factors for Orchard Heaters
6.10-1 Emission Factors for Production of Phosphate Fertilizers
6.11-1 Emission Factors for Starch Manufacturing
7.1-1 Raw Material and Energy Requirements for Aluminum Production
7.1-2 Representative Particle Size Distributions of Uncontrolled Effluents from Prebake and
Horizontal-Stud Soderberg Cells
7.1-3 Emission Factors for Primary Aluminum Production Processes
7.2-1 Emission Factors for Metallurgical Coke Manufacture without Controls
7.3-1 Emission Factors for Primary Copper Smelters without Controls
7.4- Emission Factors for Ferroalloy Production in Electric Smelting Furnaces
7.5- Emission Factors for Iron and Steel Mills
7.6- Emission Factors for Primary Lead Smelting Processes without Controls
7.6- Efficiencies of Representative Control Devices Used with Primary Lead Smelting Operations . .
7.7- Emission Factors for Primary Zinc Smelting without Controls
7.8- Particulate Emission Factors for Secondary Aluminum Operations
7.9-1 Particulate Emission Factors for Brass and Bronze Melting Furnaces without Controls
7.10-1 Emission Factors for Gray Iron Foundries
7.11-1 Emission Factors for Secondary Lead Smelting Furnaces without Controls
Page
5.2-2
5.3-4
5.4-1
5.5-2
5.64
5.7-1
5.8-1
5.9-3
5.10-2
5.11-2
5.12-5
5.13-1
5.14-2
5.15-1
5.16-1
5.17-5
5.17-7
5.17-8
S.I 8-2
5.19-1
5.20-1
5.21-1
6.1-2
6.2-1
6.3-1
6.4-2
6.4-3
6.4-4
6.5-2
6.6-3
6.7-1
6.8-2
6.9-4
6.10-1
6.11-1
7.1-2
7.1-4
7.1-5
7.2-2
7.3-2
7.4-2
7.5-4
7.6-4
7.6-5
7.7-1
7.8-1
7.9-2
7.10-1
7.11-2
xix
-------
Table Page
7.11-2 Efficiencies of Paniculate f.on'ioS Equipment Associated with Secondary I^ead Smelting
Furnaces . , 7.11-3
7.11-3 Representative Particie Si/t Dtsuib^jon from Combined Blast and Reverberator;/ Furnace Gas
Stream . , 7.11-3
7.12-1 Emission Factors for Ma£nesmr<: Srntlfins , ... 7.12-1
7.! 3-1 Emission Factors for Steel Feus*dries 7.13-2
7.14-1 Paniculate Emission Factors !"=» Se-'.-rida'-y Zinc Smelting 7.14-2
8.1-1 Parficuiate Emission Factors if., Aspnait'C C'on-'tete Plants 8.1-4
8.2-1 Emission Factors for Arrhait Koclrif .M.,-,-jfa sung without Controls 8.2-1
8.3-1 Enission Factor; fo 8ru;V M:n-jtv vv.-iwit-, >ut font's.is 8.3-3
8.4-1 Emission Factors for Caltium Carbine Pknts 8.4-1
8.5-1 Particulate Emission Factors for fasfahle Refractories Manufacturing 8.5-1
S.6-1 Emission Factors for I cnient Ki.ji'.bJ^^Siiraig wi.hout Controls 8.6-3
8.6-2 Si/e Distribution of Dust Emn-vd from Kiln Operations without Controls 8.6-4
8.7-1 Particular Emission Factors io: Ce;amic I'lav Manufacturing 8.7-1
8.8-1 Paniculate Emission Factors tor Smteiing Operations 8.8-2
8.9-1 Particulate Emission Factors lor fhmna! (\>a! Uryeis 8.9-1
8.10-1 Puiiiculate Emission factor*. IVr Concrete Bate? -ng 8.10-1
8.11-1 Emission Factors for ! iber C/hss Manutai.tut,!:g without (ontiols 8.11-3
8.12-1 Emission Factors foi cnt S'.ielt-'-s -v'thout Conuols 8.12-2
8.13-1 Emission Factors loi (iluss i1o-";i; 8.13-1
8.14-! ParUctii.ue Emission !-aci.'.'s K>; dvivsum Pi 00.-sing 8.14-i
8.15-1 I'niiask-;. Factors for Lime Manu'au-'/in;.- 8.15-4
8.16-i I russii.r Factors foi Mmtfjl ti F'uinaccs without Controls 8.17-1
8.18-1 I'arSivUlate Emissio'i F,i<.!0'r, • ;: Pht.'.piutc Ko,^ PiocesMiig without Cuitiols 8.18-1
8.20-1 l-tirtici'idte Emission FaiUns ;.). R.xk HaniJlip, PMKCSSCS 8.20-1
9.1-i i 'ii^sion I:actois tor Pet-oleum R-MVivo: , . ... 9.1-3
9.2-1 ttiiission Factors 1'of Gas Swe.--teninjT PlanJs 9.2-3
9.2-2 Average Hydrogen Sulfide Concentrations in Natural Gas by Air Quality Control Rejrjon 9.2-4
10.1.2-1 F.nifsion Fac!--. > fo- Suliaic Pislpmg 10.1-5
10.1.3-' jmif-sion Factors for Solfik-Pulping 10.1-8
10.2-1 Partunlate Emission t ;K ss '-^ Puiphoaul M-jnuiacturme 10.2-!
10.3-1 ^'iii- ru, -..i-tois !oi Pl> w*-.\: M inu! i-f 1'Xi'j-ate ; F'ld r.-iisunrd b> Forest Fires 11.1-2
11.1-2 Sumns. :>'ot L'miSMO!!. i:'.** I m.ssion Fac'-us tor Forest Wildfires .... 11.1-4
1 1.2.1-' Control Methods lor * 'iipav:,.,. Roads 1 1.2-4
1 1.2.3-1 / gregaU' Storage Fu s,<. 1 1.2.3-1
A-1 Jationwide J. i-ii- .. t .,''•. i . . . .... A.">
A-2 Distribution h; "'n . •' ";-T- * Xv^suut C •': \'\- '; ;i ic^oies foi Various Particulate Control
' quipment .... . .... A-3
A-3 'he.mal Equivalent, o; x-'.i • ." '<''.'-If- . . , . . A-4
A-4 Weights of Selected Sub5t.,'t,- - A_4
A-5 (>e "a! Conversion F"acu)i^ , A-5
B-l Pi ..ulg.'.ied New Source Pert inr.ance Standards B-2
B-2 P'onHifgjti-d New Source Performance Standaids B-4
-------
LIST OF FIGURES
Figure Page
1.4-1 Lead Reduction Coefficient as Function of Boiler Load 1.4-2
3.3.2-1 Nitrogen Oxide Emissions from Stationary Internal Combustion Engines 3.3.2-2
4.1-1 Percloroethylene Dry Cleaning Plant Flow Diagram 4.1-2
4.3-1 Flowsheet of Petroleum Production, Refining, and Distribution Systems 4.3-2
4.3-2 Fixed Roof Storage Tank 4.3-3
4.3-3 Pan Type Floating Roof Storage Tank 4.3-3
4.3-4 Double Deck Floating Roof Storage Tank 4.3-3
4.3-5 Covered Floating Roof Storage Tank 4.3-4
4.3-6 Lifter Roof Storage Tank 4.3-4
4.3-7 Flexible Diaphragm Tank 4.3-5
4.3-8 Vapor Pressures of Gasolines and Finished Petroleum Products 4.3-8
4.3-9 Vapor Pressures of Crude Oil 4.3-9
4.3-10 Adjustment Factor (C) for Small Diameter Tanks 4.3-10
4.3-11 Turnover Factor (KN) for Fixed Roof Tanks 4.3-11
4.4-1 Flowsheet of Petroleum Production, Refining, and Distribution Systems 4.4-2
4.4-2 Splash Loading Method 4.4-3
4.4-3 Submerged Fill Pipe 4.4-3
4.4-4 Bottom Loading 4.4-4
4.4-5 Tanktruck Unloading Into an Underground Service Station Storage Tank 4.4-5
4.4-6 Tanktruck Loading with Vapor Recovery 4.4-9
4.4-7 Automobile Refueling Vapor Recovery System 4.4-12
5.1-1 General Flow Diagram of Adipic Acid Manufacturing Process 5.1-3
5.3-1 Simplified Flow Diagram of Carbon Black Production by the Oil-Fired Furnace Process 5.3-2
5.6-1 Flow Diagram of Typical Batch Process TNT Plant 5.6-2
5.9-1 Flow Diagram of Typical Nitric Acid Plant Using Pressure Process 5.9-2
5.12-1 Flow Diagram for Phthalic Anhydride using O-Xylene as Basic Feftdstock 5.12-3
5.J2-2 Flow Diagram for Phthalic Anhydride using Naphthalene as Basic Feedstock 5.12^t
5.17-1 Basic Flow Diagram of Contact-Process Sulfuric Acid Plant Burning Elemental Sulfur 5.17-2
5.17-2 Basic Flow Diagram of Contact-Process Sulfuric Acid Plant Burning Spent Acid 5.17-3
5.17-3 Sulfuric Acid Plant Feedstock Sulfur Conversion Versus Volumetric and Mass S02 Emissions at
Various Inlet S02 Concentrations by Volume 5.17-6
5.18-1 Basic Flow Diagram of Modified Claus Process with Two Converter Stages Used in Manufacturing
Sulfur 5.18-2
6.1-1 Generalized Flow Diagram for Alfalfa Dehydration Plant 6.1-3
6.6-1 A Generalized Fish Processing Flow Diagram 6.6-2
6.9-1 Types of Orchard Heaters 6.9-2
6.9-2 Particulate Emissions from Orchard Heaters 6.9-3
7.1-1 Schematic Diagram of Primary Aluminum Production Process 7.1-3
7.5-1 Basic Flow Diagram of Iron and Steel Processes 7.5-2
7.6-1 Typical Flowsheet of Pyrometallurgical Lead Smelting 7.6-2
7.11-1 Secondary Lead Smelter Processes 7.11-2
8.1-1 Batch Hot-Mix Asphalt Plant 8.1-2
8.1-2 Continuous Hot-Mix Asphalt Plant 8.1-3
8.3-1 Basic Flow Diagram of Brick Manufacturing Process 8.3-2
8.6-1 Basic Row Diagram of Portland Cement Manufacturing Process 8.6-2
8.11-1 Typical Flow Diagram of Textile-Type Glass Fiber Production Process 8.11-2
8.11-2 Typical Flow Diagram of Wool-Type Glass Fiber Production Process 8.11-2
8.15-1 Generalized Lime Manufacturing Plant 8.15-2
9.1-1 Basic Flow Diagram of Petroleum Refinery 9.1-2
9.2-1 Generalized Flow Diagram of the Natural Gas Industry 9.2-2
xxi
-------
LIST OF FIGURES-(Continued)
Figure Page
9.2-2 Flow Diagram of the Amine Process Gas Sweetening 9.2-3
10.1.2-1 Typical Kraft Sulfate Pulping and Recovery Process 10.1-2
10.1.3-1 Simplified Process Flow Diagram of Magnesium-Base Process Employing Chemical and Heat
Recovery 10.1-6
11.1-1 Forest Areasand U.S. Forest Service Regions 11.1-3
11.2-1 Mean Number of Days with 0.01 inch or more of Annual Precipitation in United States 11.2-3
11.2-2 Map of Thornthwaites Precipitation-Evaporation Index Values for State Climatic Divisions 11.2.2-3
B-2 Promulgated New Source Performance Standards B-l
XXI1
-------
ABSTRACT
Emission data obtained from source tests, material balance studies, engineering estimates, etc., have been
compiled for use by individuals and groups responsible for conducting air pollution emission inventories.
Emission factors given in this document, the result of the expansion and continuation of earlier work, cover most
of the common emission categories: fuel combustion by stationary and mobile sources; combustion of solid wastes;
evaporation of fuels, solvents, and other volatile substances; various industrial processes; and miscellaneous sources.
When no source-test data are available, these factors can be used to estimate the quantities of primary pollutants
(particulates, CO, SC>2, NOX, and hydrocarbons) being released from a source or source group.
Key words: fuel combustion, stationary sources, mobile sources, industrial processes, evaporative losses, emissions,
emission data, emission inventories, primary pollutants, emission factors.
XXlll
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1. EXTERNAL COMBUSTION SOURCES
External combustion sources include steam-electric generating plants, industrial boilers, commercial and
institutional boilers, and commercial and domestic combustion units. Coal, fuel oil, and natural gas are the major
fossil fuels used by these sources. Other fuels used in relatively small quantities are liquefied petroleum gas, wood,
coke, refinery gas, blast furnace gas, and other waste- or by-product fuels. Coal, oil, and natural gas currently
supply about 95 percent of the total thermal energy consumed in the United States. In 1970 over 500 million
tons (454 x 106 MT) of coal, 623 million barrels (99 x 109 liters) of distillate fuel oil, 715 million barrels (114 x
109 liters) of residual fuel oil, and 22 trillion cubic feet (623 x 1012 liters) of natural gas were consumed in the
United States.'
Power generation, process heating, and space heating are some of the largest fuel-combustion sources of sulfur
oxides, nitrogen oxides, and particulate emissions. The following sections present emission factor data for the
major fossil fuels — coal, fuel oil, and natural gas — as well as for liquefied petroleum gas and wood waste
combustion in boilers.
REFERENCE
1. Ackerson, D.H. Nationwide Inventory of Air Pollutant Emissions. Unpublished report. Office of Air and Water
Programs, Environmental Protection Agency, Research Triangle Park, N.C. May 1971.
1.1 BITUMINOUS COAL COMBUSTION
1.1.1 General
Revised by Robert Rosensteel
and Thomas Lahre
Coal, the most abundant fossil fuel in the United States, is burned in a wide variety of furnaces to produce
heat and steam. Coal-fired furnaces range in size from small handfired units with capacities of 10 to 20 pounds
(4.5 to 9 kilograms) of coal per hour to large pulverized-coal-fired units, which may burn 300 to 400 tons (275 to
360 MT) of coal per hour.
Although predominantly carbon, coal contains many compounds in varying amounts. The exact nature and
quantity of these compounds are determined by the location of the mine producing the coal and will usually
affect the final use of the coal.
1.1.2 Emissions and Controls
1.1.2.1 Particulates1 - Particulates emitted from coal combustion consist primarily of carbon, silica, alumina, and
iron oxide in the fly-ash. The quantity of atmospheric particulate emissions is dependent upon the type of
combustion unit in which the coal is burned, the ash content of the coal, and the type of control equipment used.
4/73
1.1-1
-------
Table 1.1-1 gives the range of collection efficiencies for common types of fly-ash control equipment. Particulate
emission factors expressed as pounds of particulate per ton of coal burned are presented in Table 1.1-2.
1.1.2.2 Sulfur Oxides11 - Factors for uncontrolled sulfur oxides emission are shown in Table 1-2 along with
factors for other gases emitted. The emission factor for sulfur oxides indicates a conversion of 95 percent of the
available sulfur to sulfur oxide. The balance of the sulfur is emitted in the fly-ash or combines with the slag or ash
in the furnace and is removed with them.1 Increased attention has been given to the control of sulfur oxide
emissions from the combustion of coal. The use of low-sulfur coal has been recommended in many areas; where
low-sulfur coal is not available, other methods in which the focus is on the removal of suifur oxide from the flue
gas before it enters the atmosphere must be given consideration.
A number of flue-gas desulfurization processes have been evaluated; effective methods are undergoing full-scale
operation. Processes included in this category are: limestone-dolomite injection, limestone wet scrubbing,
catalytic oxidation, magnesium oxide scrubbing, and the Wellman-Lord process. Detailed discussion of various
flue-gas desulfurization processes may be found in the literature.12,13
1.1.2.3. Nitrogen Oxides1'5 - Emissions of oxides of nitrogen result not only from the high temperature reaction
of atmospheric nitrogen and oxygen in the combustion zone, but also from the partial combustion of nitrogenous
compounds contained in the fuel. The important factors that affect NOX production are: flame and furnace
temperature, residence time of combustion gases at the flame temperature, rate of cooling of the gases, and
amount of excess air present in the flame. Discussions of the mechanisms involved are contained in the indicated
references.
1.1.2.4 Other Gases - The efficiency of combustion primarily determines the carbon monoxide and hydrocarbon
content of the gases emitted from bituminous coal combustion. Successful combustion that results in a low level
of carbon monoxide and organic emissions requires a high degree of turbulence, a high temperature, and
sufficient time for the combustion reaction to take place. Thus, careful control of excess air rates, the use of high
combustion temperature, and provision for intimate fuel-air contact will minimize these emissions.
Factors for these gaseous emissions are also presented in Table 1.1-2. The size range in Btu per hour for the
various types of furnaces as shown in Table 1.1-2 is only provided as a guide in selecting the proper factor and is
not meant to distinguish clearly between furnace applications.
TABLE 1.1-1. RANGE OF COLLECTION EFFICIENCIES FOR COMMON TYPES
OF FLY-ASH CONTROL EQUIPMENT3
Type of
furnace
Cyclone furnace
Pulverized unit
Spreader stoker
Other stokers
Range of collection efficiencies, %
Electrostatic
precipitator
65 to 99.5b
80 to 99.5b
99.5b
99.5b
High-
efficiency
cyclone
30 to 40
65 to 75
85 to 90
90 to 95
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resistance
cyclone
20 to 30
40 to 60
70 to 80
75 to 85
Settling
chamber ex-
panded chimney
bases
10b
20b
20 to 30
25 to 50
References 1 and 2.
maximum efficiency to be expected for this collection device applied to this type source.
1.1-2
EMISSION FACTORS
4/73
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External Combustion Sources
1.1-3
-------
References for Section 1.1
1. Smith. W. S. Atmospheric hmissions from Coal Combustion. U.S. DHHVV, PUS. National Center for Air
Pollution Control. Cincinnati. Ohio. PHS Publication Number 999-AP-24. April 1966.
2. Control Techniques for Paniculate Air Pollutants. U.S. DHEW, PUS. EHS. Manorial Air Pollution Control
Administration Washington. D.C. Publication Number AP-51. January 1969.
3. Perry, H. and J. H. Field. Air Pollution and the Coal Industry. Transactions of the Society of Mining
Engineers. 238:331-345, December 1967
4. Heller, A. W. and D. F. Walters. Impact of Changing Patterns of Energy Use on Community Air Quality. J. *
Air Pol. Control Assoc. 75:426, September 1965
5. Cuffe, S. T. and R. W. Gerstle. Emissions from Coal-Fired Power Plants: A Comprehensive Summary. U.S. *
DHEW, PHS, National Air Pollution Control ,dministration. Raleigh, N. C. PHS Publication Number
999-AP-35. 1967. p. 15.
6. Austin, H. C. Atmospheric Pollution Problems of the Public Utility Industry. J. Air Pol. Control Assoc.
70(4)'292-294, August 1960.
7. Hangebrauck, R. P., D. S. Von Lehmden, and J. E. Meeker. Emissions of Polynuclear Hydrocarbons and
Other Pollutants from Heat Generation and Incineration Processes. J. Air Pol. Control Assoc. 74:267-278,
July 1964.
8. Hovey, H. H., A. Risman, and J. F. Cunnan. The Development of Air Contaminant Emission Tables for
Nonprocess Emissions. J. Air Pol. Control Assoc. 7<5'362-366, July 1966
9. Anderson, D. M., J. Lieben, and V. H. Sussman. Pure Air for Pennsylvania. Pennsylvania Department of
Health. Harrisburg, Pa. November 1961. p. 91-95.
10. Communication with National Coal Association. Washington, D. C. September 1969.
11. Private communication with R.D. Stern, Control Systems Division, Environmental Protection Agency.
Research Triangle Park, N.C. June 21, 1972.
12. Control Techniques for Sulfur Oxide Air Pollutants. U.S. DHEW, PHS, EHS, National Air Pollution Control
Administration. Washington, D.C. Publication Number AP-52. January 1969. p. xviii and xxii.
13. Air Pollution Aspects of Emission Sources: Electric Power Production. Environmental Protection Agency,
Office of Air Programs. Research Triangle Park. N.C. Publication Number AP-96. May 1971.
1.1-4 EMISSION FACTORS 4/76
-------
1.2 ANTHRACITE COAL COMBUSTIC-N revised by Tom Lahre
1.2.1 General ^2
Anthracite is a high-rank coal having a high fixed-carbon content and low volatile-matter content
relative to bituminous coal and lignite It is also characterized h> higher ignition and ash fusion tem-
peratures. Because of its low volatile-matter content and non-^linkerinn characteristics, anthracite is
most commonly fired in medium-sized, traveling-grate stoker* and small hand-fired units. Some an-
thracite (occasionally along with petroleum roke) is fired in puiveri/ed-coal-fired boilers. None is fired
in spreader stokers. Because of its low sulfui content (lvp»cally less than 0.8 percent, by weight) and
minimal smoking tendencies, anthracite is considered a desirable fuel where rradilv available.
In the United States, all anthracite is mined in Northear.tern Pennsylvania and consumed primarily
in Pennsylvania and several surrounding states. The largest use of anthracite is {or space heating; lesser
amounts are employed for steam-electric production, cok<- manufacturing, sintering and pelletizing,
and other industrial uses. Anthracite combustion currently represents only a small fraction of the to-
tal quantity of coal combusted in the United States.
1.2.2 Emissions and Controls2^9
Particulate emissions from anthracite combustion are a function of furnace-firing configuration,
firing practices (boiler load, quantity and location of underfire air, sootblowing. flyash reinjection,
etc.), as well as of the ash content of the coal. Pulverized-coal-fired boilers emit the highest quantity of
particulate per unit of fuel because they fire the anthracite in suspension, which results in a high per-
centage of ash carryover into the exhaust gases. Travelinp-grate stokers and hand-fired units, on the
other hand, produce much less particulate per unit of fuel fired. 1'bis ii because combustion takes
place in a quiescent fuel bed and does not result in significant ash carryover into the exhaust gases. In
general, particulate emissions from traveling-grate stoker* *vill increase during v jtblowing, fly-
ash reinjection, and with higher underfeed air rales through .a* fuei bed. Higher urui i feed air rates,
in turn, result from higher grate loadings arid the use of forced-'Iraft fans rather thai! n--lural draft to
supply combustion air. Smoking is rarely a problem L:;ea<»se of anlh^acite'h !ow volatile-matter
content.
Limited data are available on the emission of gaseous pollutants from anthracite combustion. It is
assumed, based on data derived from bituminous coal combustion, that a large fraction of the fuel sul-
fur is emitted as sulfur oxides. Moreover, because combustion equipment, excess air rates, combustion
temperatures, etc., are similar between anthracite and bituminous coal combustion, nitrogen oxide
and carbon monoxide emissions are assumed to be similar, as well. On the other hand, hydrocarbon
emissions are expected to be considerably lower because the volatile-matter content of anthracite is
significantly less than that of bituminous coal.
Air pollution control of emissions from anthracite combustion has mainly been limited to particu-
late matter. The most efficient particulate controls-fabric filters, scrubbers, and electrostatic precipi-
tators-have been installed on large pulverized-anthracite-fired boilers. Fabric filters and venturi
scrubbers can effect collection efficiencies exceeding 99 percent. Electrostatic precipitators, on the
other hand, are typically only 90 to 97 percent efficient due to the characteristic high resistivity of the
low-sulfur anthracite flyash. Higher efficiencies can reportedly be achieved using larger precipitators
and flue gas conditioning. Mechanical collectors are frequently employed upstream from these devices
for large-particle removal.
Traveling-grate stokers are often uncontrolled. Indeed, particulate control has often been con-
sidered unnecessary because of anthracite's low smoking tendencies and due to the fact that a signifi-
cant fraction of the large-sized flyash from stokers is readily collected in flyash hoppers as well as in the
breeching and base of the stack. Cyclone collectors have been employed on traveling-grate stokers;
4/77 External Combustion Sources 1.2-1
-------
limited information suggests these devices may be up to 75 percent efficient on particulate. Flyash rein-
jection, frequently employed in traveling-grate stokers to enhance fuel-use efficiency, tends to in-
crease particulate emissions per unit of fuel combusted.
Emission factors for anthracite combustion are presented in Table 1.2-1.
1.2-2 EMISSION FACTORS 4/7
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External Combustion Sources
1.2-3
-------
1.3 FUEL OIL COMBUSTION by Tom Lahre
1.3.1 General1'2
Fuel oils are broadly classified into two major types, distillate and residual. Distillate oils (fuel oil grades 1 and
2) are used mainly in domestic and small commercial applications in which easy fuel burning is required.
Distillates are more volatile and less viscous, than residual oils as well as cleaner, having negligible ash and nitrogen
contents and usually containing less than 0.3 percent sulfur (by weight). Residual oils (fuel oil grades 4, 5, and 6),
on the other hand, are used mainly in utility, industrial, and large commercial applications in which sophisticated
combustion equipment can be utilized. (Grade 4 oil is sometimes classified as a distillate; grade 6 is sometimes
referred to as Bunker C.) Being more viscous and less volatile than distillate oils, the heavier residual oils (grades 5
and 6) must be heated for ease of handling and to facilitate proper atomization. Because residual oils are
produced from the residue left over after the lighter fractions (gasoline, kerosene, and distillate oils) have been
removed from the crude oil, they contain significant quantities of ash, nitrogen, and sulfur. Properties of typical
fuel oils are given in Appendix A.
1.3.2 Emissions
Emissions from fuel oil combustion are dependent on the grade and composition of the fuel, the type and size
of the boiler, the firing and loading practices used, and the level of equipment maintenance. Table 1.3-1 presents
emission factors for fuel oil combustion in units without control equipment. Note that the emission factors for
industrial and commercial boilers are divided into distillate and residual oil categories because the combustion of
each produces significantly different emissions of particulates, SOX, and NOX. The reader is urged to consult the
references cited for a detailed discussion of all of the parameters that affect emissions from oil combustion.
1.3.2.1 Particulates ' - Particulate emissions are most dependent on the grade of fuel fired. The lighter
distillate oils lesult in significantly lower particulate formation than do the heavier residual oils. Among residual
oils, grades 4 and 5 usually result in less particulate than does the heavier grade 6.
In boilers firing grade 6. particulate emissions can be described, on the average, as a function of the sulfur
content of the oil. As shown in Table 1.3-1 (footnote c), particulate emissions can be reduced considerably when
low-sulfur grade 6 oil is fired. This is because low-sulfur grade 6, whether refined from naturally occurring
low-sulfur crude oil or desulfunzed by one of several processes currently in practice, exhibits substantially lower
viscosity and reduced asphaltene, ash, and sulfur content - all of which result in better atomization and cleaner
combustion.
Boiler load can also affect particulate emissions in units firing grade 6 oil. At low load conditions, particulate
emissions may be lowered by 30 to 40 percent from utility boilers and by as much as 60 percent from small
industrial and commercial units. No significant particulate reductions have been noted at low loads from boilers
firing any of the lighter grades, however. At too low a load condition, proper combustion conditions cannot be
maintained and particulate emissions may increase drastically. It should be noted, in this regard, that any
condition that prevents proper boiler operation can result in excessive particulate formation.
1.3.2 2 Sulfur Oxides (SOX) " - Total sulfur oxide emissions are almost entirely dependent on the sulfur
content of the fuel and are not affected by boiler size, burner design, or grade of fuel being fired. On the average,
more than 95 percent of the fuel sulfui is converted to SO2, with about 1 to 3 percent further oxidized to 803.
Sulfur tnoxide readily reacts with water vapor (both in the air and in the flue gases) to form a sulfuric acid mist.
4/77 External Combustion Sources 1.3-1
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1.3.2.3 Nitrogen Oxides (NOx)1"6' 8"11' 14 - Two mechanisms form nitrogen oxides: oxidation of fuel-bound
nitrogen and thermal fixation of the nitrogen present in combustion air. Fuel NOX are primarily a function of the
nitrogen content of the fuel and the available oxygen (on the average, about 45 percent of the fuel nitrogen is
converted to NOX, but this may vary from 20 to 70 percent). Thermal NOX, on the other hand, are largely a
function of peak flame temperature and available oxygen - factors which are dependent on boiler size, firing
configuration, and operating practices.
Fuel nitrogen conversion is the more important N0x-forming mechanism in boilers firing residual oil. Except
in certain large units having unusually high peak flame temperatures, or in units firing a low-nitrogen residual oil,
fuel NOX will generally account for over 50 percent of the total NOX generated. Thermal fixation, on the other
hand, is the predominant N0x-forming mechanism in units firing distillate oils, primarily because of the negligible
nitrogen content in these lighter oils. Because distillate-oil-fired boilers usually have low heat release rates,
however, the quantity of thermal NOX formed in them is less than in larger units.
A number of variables influence how much NOX is formed by these two mechanisms. One important variable
is firing configuration. Nitrogen oxides emissions from tangentially (corner) fired boilers are, on the average, only
half those of horizontally opposed units. Also important are the firing practices employed during boiler operation.
The use of limited excess air firing, flue gas recirculation, staged combustion, or some combination thereof, may
result in NOX reductions ranging from 5 to 60 percent. (See section 1.4 for a discussion of these techniques.)
Load reduction can likewise decrease NOX production. Nitrogen oxides emissions may be reduced from 0.5 to 1
percent for each percentage reduction in load from full load operation. It should be noted that most of these
variables, with the exception of excess air, are applicable only in large oil-fired boilers. Limited excess air firing is
possible in many small boilers, but the resulting NOX reductions are not nearly as significant.
1.3.2.4 Other Pollutants ' ' ' — As a rule, only minor amounts of hydrocarbons and carbon monoxide
will be produced during fuel oil combustion. If a unit is operated improperly or not maintained, however, the
resulting concentrations of these pollutants may increase by several orders of magnitude. This is most likely to be
the case with small, often unattended units.
1.3.3 Controls
Various control devices and/or techniques may be employed on oil-fired boilers depending on the type of
boiler and the pollutant being controlled. All such controls may be classified into three categories: boiler
modification, fuel substitution, and flue gfes cleaning.
1.3.3.1 Boiler Modification1" ' ' ' 'l - Boiler modification includes any physical change in the boiler
apparatus itself or in the operation thereof. Maintenance of the burner system, for example, is important to
assure proper atomization and subsequent minimization of any unburned combustibles. Periodic tuning is
important in small units to maximize operating efficiency and minimize pollutant emissions, particularly smoke
and CO. Combustion modifications such as limited excess air firing, flue gas recirculation, staged combustion, and
reduced load operation all result in lowered NOx emissions in large facilities. (See Table 1.3-1 for specific
reductions possible through these combustion modifications.)
1.3.3.2 Fuel Substitution ' — Fuel substitution, that is, the firing of "cleaner" fuel oils, can substantially
reduce emissions of a number of pollutants. Lower sulfur oils, for instance, will reduce SOX emissions in all
boilers regardless of size or type of unit or grade of oil fired. Particulates will generally be reduced when a better
grade of oil is fired. Nitrogen oxide emissions will be reduced by switching to either a distillate oil or a residual oil
containing less nitrogen. The practice of fuel substitution, however, may be limited by the ability of a given
operation to fire a better grade of oil as well as the cost and availability thereof.
4/76 External Combustion Sources 1.3-3
-------
1.3.3.3 Flue Gas Cleaning ' — Flue gas cleaning equipment is generally only employed on large oil-fired
boilers. Mechanical collectors, a prevalent type of control device, are primarily useful in controlling particulates
generated during soot blowing, during upset conditions, or when a very dirty, heavy oil is fired. During these
situations, high efficiency cyclonic collectors can effect up to 85 percent control of particulate. Under normal
firing conditions, however, or when a clean oil is combusted, cyclonic collectors will not be nearly as effective.
Electrostatic precipitators are commonly found in power plants that at one time fired coal. Precipitators that
were designed for coal flyash provide only 40 to 60 percent control of oil-fired particulate. Collection efficiencies
of up to 90 percent, however, have been reported for new or rebuilt devices that were specifically designed for
oil-firing units.
Scrubbing systems have been installed on oil-fired boilers, especially of late, to control both sulfur oxides and
particulate. These systems can achieve SC>2 removal efficiencies of up to 90 to 95 percent and provide particulate
control efficiencies on the order of 50 to 60 percent. The reader should consult References 20 and 21 for details
on the numerous types of flue gas desulfurization systems currently available or under development.
References for Section 1.3
1. Smith, W. S. Atmospheric Emissions from Fuel Oil Combustion: An Inventory Guide. U.S. DHEW, PHS,
National Center for Air Pollution Control. Cincinnatti, Ohio. PHS Publication No. 999-AP-2. 1962.
2. Air Pollution Engineering Manual. Danielson, J.A. (ed.). Environmental Protection Agency. Research
Triangle Park, N.C. Publication No. AP-40. May 1973. p. 535-577.
3. Levy, A. et al. A Field Investigation of Emissions from Fuel Oil Combustion for Space Heating. Battelle
Columbus Laboratories. Columbus, Ohio. API Publication 4099. November 1971.
4. Barrett, R.E. et al. Field Investigation of Emissions from Combustion Equipment for Space Heating. Battelle
Columbus Laboratories. Columbus, Ohio. Prepared for Environmental Protection Agency, Research Triangle
Park, N.C., under Contract No. 68-02-0251. Publication No. R2-73-084a. June 1973.
5. Cato, G.A. et al. Field Testing: Application of Combustion Modifications to Contiol Pollutant Emissions
From Industrial Boilers - Phase I. KVB Engineering, Inc. Tustin, Calif. Prepared for Environmental
Protection Agency, Research Triangle Park, N.C., under Contract No. 68-02-1074. Publication No.
EPA-650/2-74-078a. October 1974.
6. Particulate Emission Control Systems For Oil-Fired Boilers. GCA Corporation. Bedford, Mass. Prepared foi
Environmental Protection Agency, Research Triangle Park, N.C., under Contract No. 68-02-1316.
Publication No. EPA-450/3-74-063. December 1974.
7. Title 40 - Protection of Environment. Part 60 - Standards of Performance for New Stationary Sources.
Method 5 - Determination of Emission from Stationary Sources. Federal Register. 36(247): 24888-24890,
December 23, 1971.
8. Bartok, W. et al. Systematic Field Study of NOX Emission Control Methods for Utility Boilers. ESSO
Research and Engineering Co., Linden, N.J. Prepared for Environmental Protection Agency, Research
Triangle Park, N.C., under Contract No. CPA-70-90. Publication No. APTD 1163. December 31, 1971.
9. Crawford, A.R. et al. Field Testing: Application of Combustion Modifications to Control NOX Emissions
From Utility Boilers. Exxon Research and Engineering Company. Linden, N.J. Prepared for Environmental
Protection Agency, Research Triangle Park, N.C., under Contract No. 68-02-0227. Publication No.
EPA-650/2-74-066. June 1974. p.l 13-145.
10. Deffner, J.F. et al. Evaluation of Gulf Econoject Equipment with Respect to Air Conservation. Gulf
Research and Development Company. Pittsburgh, Pa. Report No. 731RC044. December 18, 1972.
1.3-4 EMISSION FACTORr 4/76
-------
11. Blakeslee, C.E. and H.E. Burbach. Controlling NOX Emissions from Steam Generators. J. Air Pol. Control
Assoc. 25:37-42, January 1973.
12. Siegmund, C.W. Will Desulfurized Fuel Oils Help? ASHRAE Journal. ./;:29-33, April 1969.
13. Govan, F.A. et al. Relationship of Particulate Emissions Versus Partial to Full Load Operations For
Utility-Sized Boilers. In: Proceedings of 3rd Annual Industrial Air Pollution Control Conference, Knoxville,
March 29-30, 1973. p. 424-436.
14. Hall, R.E. et al. A Study of Air Pollutant Emissions From Residential Heating Systems. Environmental
Protection Agency. Research Triangle Park, N.C. Publication No. EPA-650/2-74-003. January 1974.
15. Perry, R.E. A Mechanical Collector Performance Test Report on an Oil Fired Power Boiler. Combustion.
May 1972. p. 24-28.
16. Burdock, J.L. Fly Ash Collection From Oil-Fired Boilers. (Presented at 10th Annual Technical Meeting of
New England Section of APCA, Hartford, April 21, 1966.)
17. Bagwell, F.A. and R.G. Velte. New Developments in Dust Collecting Equipment for Electric Utilities. J. Air
Pol. Control Assoc. 27:781-782, December 1971.
18. Internal memorandum from Mark Hooper to EPA files referencing discussion with the Northeast Utilities
Company. January 13, 1971.
19. Pinheiro, G. Precipitators for Oil-Fired Boilers. Power Engineering. 75:52-54, April 1971.
20. Flue Gas Desulfurization: Installations and Operations. Environmental Protection Agency. Washington, D.C.
September 1974.
21. Proceedings: Flue Gas Desulfurization Symposium - 1973. Environmental Protection Agency. Research
Triangle Park, N.C. Publication No. EPA-650/2-73-038. December 1973.
4/76 External Combustion Sources 1.3-5
-------
1.4 NATURAL GAS COMBUSTION Revised by Thomas Lahre
1.4.1 General U
Natural gas has become one of the major fuels used throughout the country. It is used mainly for power gen-
eration, for industrial process steam and heat production, and for domestic and commercial space heating. The
primary component of natural gas is methane, although varying amounts of ethane and smaller amounts of nitro-
gen, helium, and carbon dioxide are also present. The average gross heating value of natural gas is approximately
1050 Btu/stdft3 (9350 kcal/Nm3), varying generally between 1000 and 1100 Btu/stdft3 (8900 to 9800 kcal/
Nm3).
Because natural gas in its original state is a gaseous, homogenous fluid, its combustion is simple and can be pre-
cisely controlled. Common excess air rates range from 10 to 15 percent; however, some large units operate at
excess air rates as low as 5 percent to maximize efficiency and minimize nitrogen oxide (NOX) emissions.
1.4.2 Emissions and Controls 3-16
Even though natural gas is considered to be a relatively clean fuel, some emissions can occur from the com-
bustion reaction. For example, improper operating conditions, including poor mixing, insufficient air, etc., may
cause large amounts of smoke, carbon monoxide, and hydrocarbons to be produced. Moreover, because a sulfur-
containing mercaptan is added to natural gas for detection purposes, small amounts of sulfur oxides will also be
produced in the combustion process.
Nitrogen oxides are the major pollutants of concern when burning natural gas. Nitrogen oxide emissions are
a function of the temperature in the combustion chambei and the rate of cooling of the combustion products.
Emission levels generally vary considerably with the type and size of unit and are also a function of loading.
In some large boilers, several operating modifications have been employed for NOX control. Staged combus-
tion, for example, including off-stoichiometric firing and/or two-stage combustion, can reduce NOX emissions
by 30 to 70 percent. In off-stoichiometric firing, also called "biased firing," some burners are operated fuel-
rich, some fuel-lean, while others may supply air only. In two-staged combustion, the burners are operated fuel-
rich (by introducing only 80 to 95 percent stoichiometric air) with combustion being completed by air injected
above the flame zone through second-stage "NO-ports." In staged combustion, NOX emissions are reduced be-
cause the bulk of combustion occurs under fuel-rich, reducing conditions.
Other N0x-reducing modifications include low excess air firing and flue gas recirculation. In low excess air
firing, excess air levels are kept as low as possible without producing unacceptable levels of unburned combus-
tibles (carbon monoxide, hydrocarbons, and smoke) and/or other operational problems. This technique can re-
duce NOX emissions by 10 to 30 percent primarily because of the lack of availability of oxygen during
combustion. Flue gas recirculation into the primary combustion zone, because the flue gas is relatively cool and
oxygen deficient, can also lower NOX emissions by 20 to 60 percent depending on the amount of gas recircu-
lated. At present only a few systems have this capability, however.
Combinations of the above combustion modifications may also be employed to further reduce NOX emissions.
In some boilers, for instance, NOX reductions as high as 70 to 90 percent have been produced as a result of em-
ploying several of these techniques simultaneously. In general, however, because the net effect of any of these
combinations varies greatly, it is difficult to predict what the overall reductions will be in any given unit.
Emission factors for natural gas combustion are presented in Table 1.4-1. Flue gas cleaning equipment has
not been utilized to control emissions from natural gas combustion equipment.
5/74 External Combustion Sources 1.4-1
-------
Table 1.4-1. EMISSION FACTORS FOR NATURAL-GAS COMBUSTION
EMISSION FACTOR RATING: A
Pollutant
Particulates3
Sulfur oxides (S02)b
Carbon monoxide0
Hydrocarbons
(asCH4)d
Nitrogen oxides
(N02)e
Type of unit
Power plant
Ib/106ft3
5-15
0.6
17
1
700f-h
kg/106 m3
*" 80-240
9.6
272
16
11,200f-h
Industrial process
boiler
Ib/106ft3
5-15
0.6
17
3
(1 20-230) i
kg/106 m3
80-240
9.6
272
48
(1920-
3680) '
Domestic and
commercial heating
lb/1Q6ft3
5-15
0.6
20
8
(80-120))
kg/106 m3
80-240
9.6
320
128
(1280-
1920))
a References 4,7,8,12.
^Reference 4 (based on an average sulfur content of natural gas of 2000 gr/106 stdft-3 (4600 g/1Q6 Nm3).
cReferences 5, 8-12.
^References 8, 9, 12.
e References 3-9, 12-16.
f Use 300 lb/106 stdft3 (4800 kg/106 N/n3) for tangentially fired units.
9At reduced loads, multiply this factor by the load reduction coefficient given in Figure 1.4-1.
nSee text for potential NOX reductions due to combustion modifications. Note that the NOX reduction from these modifications
will also occur at reduced load conditions.
' This represents a typical range fo> many industrial boilers. For large industrial units (> 100 MMBtu/hr) use the NOX factors pre-
sented for power plants.
i Use 80 (1280) for domestic heating units and 120 (1920) for commercial units.
1.0
g 0.8
u.
LU
O
o
o 0.6
o
:o
o
Q
-------
References for Section 1.4
1. High, D. M. et al. Exhaust Gases from Combustion and Industrial Processes. Engineering Science, Inc.
Washington, D.C. Prepared for U.S. Environmental Protection Agency, Research Triangle Park, N.C. undei
Contract No. EHSD71-36, October 2, 1971.
2. Perry, J. H. (ed.). Chemical Engineer's Handbook. 4th Ed. New York, McGraw-Hill Book Co., 1963. p. 9-X
3. Hall, E. L. What is the Role of the Gas Industry in Air Pollution? In: Proceedings of the 2nd National Air
Pollution Symposium. Pasadena, California, 1952. p.54-58.
4. Hovey, H. H., A. Risman, and J. F. Cunnan. The Development of Air Contaminant Emission Tables for Non-
process Emissions. New York State Department of Health. Albany, New York. 1965.
5. Bartok, W. et al. Systematic Field Study of NOX Emission Control Methods for Utility Boilers. Esso Research
and Engineering Co., Linden, N. J. Prepared for U. S. Environmental Protection Agency, Research Triangle
Park, N.C. under Contract No. CPA 70-90, December 31,1971.
6. Bagwell, F. A. et al. Oxides of Nitrogen Emission Reduction Program for Oil and Gas Fired Utility Boilers.
Proceedings of the American Power Conference. Vol.32. 1970. p.683-693.
7. Chass, R. L. and R. E. George. Contaminant Emissions from the Combustion of Fuels, J. Air Pollution Control
Assoc. J0:3443, February 1960.
8. Hangebrauck, R. P., D. S. Von Lehmden, and J. E. Meeker. Emissions of Polynuclear Hydrocarbons and
other Pollutants from Heat Generation and Incineration Processes. J. Air Pollution Control Assoc. 14:211,
July 1964.
9. Dietzmann, H. E. A Study of Power Plant Boiler Emissions. Southwest Research Institute, San Antonio, Texas.
Final Report No. AR-837. August 1972.
10. Private communication with the American Gas Association Laboratories. Cleveland, Ohio. May 1970.
11. Unpublished data on domestic gas-fired units. U.S. Dept. of Health, Education, and Welfare, National Air
Pollution Control Administration, Cincinnati, Ohio. 1970.
12. Barrett, R. E. et al. Field Investigation of Emissions from Combustion Equipment for Space Heating.
Battelle-Columbus Laboratories, Columbus, Ohio. Prepared for U.S. Environmental Protection Agency,
Research Triangle Park, N.C. under Contract No. 68-02-0251. Publication No. EPA-R2-73-084. June 1973.
13. Blakeslee, C. E. and H. E. Burbock. Controlling NOX Emissions from Steam Generators. J. Air Pollution
Control Assoc. 25:37-42, January 1973.
14. Jain, L. K. et al. "State of the Art" for Controlling NOX Emissions. Part 1. Utility Boilers. Catalytic, Inc.,
Charlotte, N. C. Prepared for U.S. Environmental Protection Agency under Contract No. 68-02-0241 (Task
No. 2). September 1972.
15. Bradstreet, J. W. and JR. J. Fortman. Status of Control Techniques for Achieving Compliance with Air Pollu-
tion Regulations by the Electric Utility Industry. (Presented at the 3rd Annual Industrial Air Pollution
Control Conference. Knoxville, Tennessee. March 29-30,1973.)
16. Study of Emissions of NOX from Natural Gas-Fired Steam Electric Power Plants in Texas. Phase II. Vol. 2.
Radian Corporation, Austin, Texas. Prepared for the Electric Reliability Council of Texas. May 8, 1972,
5/74 External Combustion Sources 1.4-3
-------
-------
1.5 LIQUEFIED PETROLEUM GAS COMBUSTION Revised by Thomas Lahre
1.5.1 General1
Liquefied petroleum gas, commonly referred to as LPG, consists mainly of butane, propane, or a mixture of
the two, and of trace amounts of propvlene and butylene. This gas, obtained from oil or gas wells as a by-product
of gasoline refining, is sold as a liquid in metal cylinders under pressure and, therefore, is often called bottled gas.
LPG is graded according to maximum vapor pressure with Grade A being predominantly butane, Grade F
being predominantly propane, and Grades B through E consisting of varying mixtures of butane and propane. The
heating value of LPG ranges from 97,400 Btu/gallon (6,480 kcal/liter) for Grade A to 90,500 Btu/gallon (6,030
kcal/liter) for Grade F. The largest market for LPG is the domestic-commercial market, followed by the chemical
industry and the internal combustion engine.
1.5.2 Emissions1
LPG is considered a "clean" fuel because it does not produce visible emissions. Gaseous pollutants such as
carbon monoxide, hydrocarbons, and nitrogen oxides do occur, however. The most significant factors affecting
these emissions are the burner design, adjustment, and venting.2 Improper design, blocking and clogging of the
flue vent, and lack of combustion air result in improper combustion that causes the emission of aldehydes, carbon
monoxide, hydrocarbons, and other organics. Nitrogen oxide emissions are a function of a number of variables
including temperature, excess air, and residence time in the combustion zone. The amount of sulfur dioxide
emitted is directly proportional to the amount of sulfur in the fuel. Emission factors for LPG combustion are
presented in Table 1.5-1.
References for Section 1.5
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Clifford, E.A. A Practical Guide to Liquified Petroleum Gas Utilization. New York, Moore Publishing Co.
1962.
4/77 External Combustion Sources 1.5-1
-------
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1.5-2
EMISSION FACTORS
4/77
-------
1.6 WOOD/BARK WASTE COMBUSTION IN BOILERS Revised by Thomas Lahre
1.6.1 General 1-3
Today, the burning of wood/bark waste in boilers is largely confined to those industries where it is available as
a by-product. It is burned both to recover heat energy and to alleviate a potential solid waste disposal problem.
Wood/bark waste may include large pieces such as slabs, logs, and bark strips as well as smaller pieces such as ends,
shavings, and sawdust. Heating values for this waste range from 8000 to 9000 Btu/lb, on a dry basis; however,
because of typical moisture contents of 40 to 75 percent, the as-fired heating values for many wood/bark waste
materials range as low as 4000 to 6000 Btu/lb. Generally, bark is the major type of waste burned in pulp mills;
whereas, a variable mixture of wood and bark waste, or wood waste alone, is most frequently burned in the
lumber, furniture, and plywood industries.
1.6.2 Firing Practices 1-3
A variety of boiler firing configurations are utilized for burning wood/bark waste. One common type in
smaller operations' is the Dutch Oven, or extension type of furnace with a flat grate. In this unit the fuel is fed
through the furnace roof and burned in a cone-shaped pile on the grate. In many other, generally larger, opera-
tions, more conventional boilers have been modified to burn wood/bark waste. These units may include spreader
stokers with traveling grates, vibrating grate stokers, etc., as well as tangentially fired or cyclone fired boilers.
Generally, an auxiliary fuel is burned in these units to maintain constant steam when the waste fuel supply fluctu-
ates and/or to provide more steam than is possible from the waste supply alone.
1.6.3 Emissions 1.2,4-8
The major pollutant of concern from wood/bark boilers is particulate matter although other pollutants, par-
ticularly carbon monoxide, may be emitted in significant amounts under poor operating conditions. These
emissions depend on a number of variables including (1) the composition of the waste fuel burned, (2) the degree
of fly-ash reinjection employed, and (3) furnace design and operating conditions.
The composition of wood/bark waste depends largely on the industry from whence it originates. Pulping op-
erations, for instance, produce great quantities of bark that may contain more than 70 percent moisture (by
weight) as well as high levels of sand and other noncombustibles. Because of this, bark boilers in pulp mills may
emit considerable amounts of particulate matter to the atmosphere unless they are well controlled. On the other
hand, some operations such as furniture manufacture, produce a clean, dry (5 to 50 percent moisture) wood
waste that results in relatively few particulate emissions when properly burned. Still other operations, such as
sawmills, burn a variable mixture of bark and wood waste that results in particulate emissions somewhere in be-
tween these two extremes.
Fly-ash reinjection, which is commonly employed in many larger boilers to improve fuel-use efficiency, has a
considerable effect on particulate emissions. Because a fraction of the collected fly-ash is reinjected into the
boiler, the dust loading from the furnace, and consequently from the collection device, increases significantly
per ton of wood waste burned. It is reported that full reinjection can cause a 10-fold increase in the dust load-
ings of some systems although increases of 1.2 to 2 times are more typical for boilers employing 50 to 100 per-
cent reinjection. A major factor affecting this dust loading increase is the extent to which the sand and other
non-combustibles can be successfully separated from the fly-ash before reinjection to the furnace.
Furnace design and operating conditions are particularly important when burning wood and bark waste. For
example, because of the high moisture content in this waste, a larger area of refractory surface should be provided
to dry the fuel prior to combustion. In addition, sufficient secondary air must be supplied over the fuel bed to
burn the volatiles that account for most of the combustible material in the waste. When proper drying conditions
5/74 External Combustion Sources 1.6-1
-------
do not exist, or when sufficient secondary air is not available, the combustion temperature is lowered, incomplete
combustion occurs, and increased particulate, carbon monoxide, and hydrocarbon emissions will result.
Emission factors for wood waste boilers are presented in Table 1.6-1. For boilers where fly-ash reinjection
is employed, two factors are shown: the first represents the dust loading reaching the control equipment; the
value in parenthesis represents the dust loading after controls assuming about 80 percent control efficiency. All
other factors represent uncontrolled emissions.
Table 1.6-1. EMISSION FACTORS FOR WOOD AND BARK WASTE COMBUSTION IN BOILERS
EMISSION FACTOR RATING: B
Pollutant
Participates8
Barkb-c
With fly-ash reinjectiond
Without fly-ash reinjection
Wood/bark mixtureb.e
With fly-ash reinjectiond
Without fly-ash reinjection
Woodtg
Sulfur oxides (S02)h<'
Carbon monoxide!
Hydrocarbonsk
Nitrogen oxides (N02>1
Emissions
Ib/ton
75(15)
50
45(9)
30
5-15
1.5
2-60
2-70
10
kg/MT
37.5(7.5)
25
22.5 (4.5)
15
2.5-7.5
0.75
1-30
1-35
5
aThese emission factors were determined for boilers burning gas or oil as an auxiliary fuel, and it was assumed all particulates
resulted from the waste fuel alone. When coal is burned as an auxiliary fuel, the appropriate emission factor from Table 1.1-2
should be used in addition to the above factor.
t>These factors based on an as-fired moisture content of 50 percent.
CReferences 2, 4, 9.
dThis factor represents a typical dust loading reaching the control equipment for boilers employing fly-ash reinjection. The value
in parenthesis represents emissions after the control equipment assuming an average efficiency of 80 percent.
eRef erences 7, 10.
f This waste includes clean, dry (5 to 50 percent moisture) sawdust, shavings, ends, etc., and no bark. For well designed and
operated boilers use lower value and higher values for others. This factor is expressed on an as-fired moisture content basis as-
suming no fly-ash reinjection.
QReferences 11-13.
"This factor is calculated by material balance assuming a maximum sulfur content of 0.1 percent in the waste. When auxiliary
fuels are burned, the appropriate factors from Tables 1.1-2,1.3-1, or 1.4-1 should be used in addition to determine sulfur oxide
emissions.
iReferences 1, 5, 7.
IThis factor is based on engineering judgment and limited data from references 11 through 13. Use lower values for well designed
and operated boilers.
^This factor is based on limited data from references 13 through 15. Use lower values for well designed and operated boilers.
1 Reference 16.
References for Section 1.6
1. Steam, Its Generation and Use, 37th Ed. New York, Babcock and Wilcox Co., 1963. p. 19-7 to 19-10 and
3-A4.
2. Atmospheric Emissions from the Pulp and Paper Manufacturing Industry. U.S. Environmental Protection
Agency, Research Triangle Park, N.C. Publication No. EPA-450/1-73-002. September 1973.
1.6-2
EMISSION FACTORS
5/74
-------
3. C-E Bark Burning Boilers. Combustion Engineering, Inc., Windsor, Connecticut. 1973.
4. Barren, Jr., Alvah. Studies on the Collection of Bark Char Throughout the Industry. TAPPI. 5 3(8): 1441 -1448,
August 1970.
5. Kreisinger, Henry. Combustion of Wood-Waste Fuels. Mechanical Engineering. 61:115-120, February 1939.
6. Magill,P.L.etal. (eds.). Air Pollution Handbook. New York, McGraw-Hill Book Co., 1956. p. 1-15 and 1-16.
7. Air Pollutant Emission Factors. Final Report. Resources Research, Inc., Reston, Virginia. Prepared for U.S.
Environmental Protection Agency, Durham, N.C. under Contract No. CPA-22-69-119. April 1970. p. 247 to
2-55.
8. Mullen, J. F. A Method for Determining Combustible Loss, Dust Emissions, and Recirculated Refuse for a
Solid Fuel Burning System. Combustion Engineering, Inc., Windsor, Connecticut.
9. Source test data from Alan Lindsey, Region IV, U.S. Environmental Protection Agency, Atlanta, Georgia.
May 1973.
10. Effenberger, H. K. et al. Control of Hogged-Fuel Boiler Emissions: A Case History. TAPPI. 56(2):111-115,
February 1973.
11. Source test data from the Oregon Department of Environmental Quality, Portland, Oregon. May 1973.
12. Source test data from the Illinois Environmental Protection Agency, Springfield, Illinois. June 1973.
13. Danielson, J. A. (ed.). Air Pollution Engineering Manual. U.S. Department of Health, Education, and Welfare,
PHS, National Center for Air Pollution Control, Cincinnati, Ohio. Publication No. 999-AP-40. 1967.
p. 436-439.
14. Droege, H. and G. Lee. The Use of Gas Sampling and Analysis for the Evaluation of Teepee Burners. Bureau
of Air Sanitation, California Department of Public Health. (Presented at the 7th Conference on Methods in
Air Pollution Studies, Los Angeles. January 1967.)
15. Junge, D. C. and R. Kwan. An Investigation of the Chemically Reactive Constituents of Atmospheric Emis-
sions from Hog-Fuel Boilers in Oregon. PNWIS-APCA Paper No. 73-AP-21. November 1973.
16. Galeano, S. F. and K. M. Leopold. A Survey of Emissions of Nitrogen Oxides in the Pulp Mill. TAPPI.
56(3):74-76, March 1973.
5/74 External Combustion Sources 1.6-3
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1,7 LIGNITE COMBUSTION by Thomas Lahre
1.7.1 General1"4
Lignite is a geologically young coal whose properties are intermediate to those of bituminous coal and peat. It
has a high moisture content (35 to 40 percent, by weight) and a low heating value (6000 to 7500 Btu/lb, wet
basis) and is generally only burned close to where it is mined, that is, in the midwestern States centered about
North Dakota and in Texas. Although a small amount is used in industrial and domestic situations, lignite is
mainly used for steam-electric production in power plants. In the past, lignite was mainly burned in small stokers;
today the trend is toward use in much larger pulverized-coal-fired or cyclone-fired boilers.
The major advantage to firing lignite is that, in certain geographical areas, it is plentiful, relatively low in cost,
and low in sulfur content (0.4 to 1 percent by weight, wet basis). Disadvantages are that more fuel and larger
facilities are necessary to generate each megawatt of power than is the case with bituminous coal. There are
several reasons for this. First, the higher moisture content of lignite means that more energy is lost in the gaseous
products of combustion, which reduces boiler efficiency. Second, more energy is required to grind lignite to the
specified size needed for combustion, especially in pulverized coal-fired units. Third, greater tube spacing and
additional soot blowing are required because of the higher ash-fouling tendencies of lignite. Fourth, because of its
lower heating value, more fuel must be handled to produce a given amount of power because lignite is not
generally cleaned or dried prior to combustion (except for some drying that may occur in the crusher or
pulverizer and during subsequent transfer to the burner). Generally, no major problems exist with the handling or
combustion of lignite when its unique characteristics are taken into account.
1.7.2 Emissions and Controls 2'8
The major pollutants of concern when firing lignite, as with any coal, are particulates, sulfur oxides, and
nitrogen oxides. Hydrocarbon and carbon monoxide emissions are usually quite low under normal operating
conditions.
Particulate emissions appear most dependent on the firing configuration in the boiler. Pulverized-coal-fired
units and spreader stokers, which fire all or much of the lignite in suspension, emit the greatest quantity of flyash
per unit of fuel burned. Both cyclones, which collect much of the ash as molten slag in the furnace itself, and
stokers (other than spreader stokers), which retain a large fraction of the ash in the fuel bed, emit less particulate
matter. In general, the higher sodium content of lignite, relative to other coals, lowers particulate emissions by
causing much of the resulting flyash to deposit on the boiler tubes. This is especially the case in
pulverized-coal-fired units wherein a high fraction of the ash is suspended in the combustion gases and can readily
come into contact with the boiler surfaces.
Nitrogen oxides emissions are mainly a function of the boiler firing configuration and excess air. Cyclones
produce the highest NOX levels, primarily because of the high heat-release rates and temperatures reached in the
small furnace sections of the boiler. Pulverized-coal-fired boilers produce less NOX than cyclones because
combustion occurs over a larger volume, which results in lower peak flame temperatures. Tangentially fired
boilers produce the lowest NO levels in this category. Stokers produce the lowest NO levels mainly because
most existing units are mucfi smaller than the other firing types. In most boilers, regardless of firing
configuration, lower excess air during combustion results in lower NO emissions.
X
Sulfur oxide emissions are a function of the alkali (especially sodium) content of the lignite ash. Unlike most
fossil fuel combustion, in which over 90 percent of the fuel sulfur is emitted as SO2, a significant fraction of
the sulfur in lignite reacts with the ash components during combustion and is retained in the boiler ash deposits and
flyash. Tests have shown that less than 50 percent of the available sulfur may be emitted as S02 when a
high-sodium lignite is burned, whereas, more than 90 percent may be emitted with low-sodium lignite. As a rough
average, about 75 percent of the fuel sulfur will be emitted as S02, with the remainder being converted to various
sulfate salts.
12/75 External Combustion Sources 1.7-1
-------
Air pollution controls on lignite-fired boilers in the United States have mainly been limited to cyclone
collectors, which typically achieve 60 to 75 percent collection efficiency on lignite flyash. Electrostatic
precipitators, which are widely utilized in Europe on lignitic coals and can effect 99+ percent paniculate control,
have seen only limited application in the United States to date although their use will probably become
widespread on newer units in the future.
Nitrogen oxides reduction (up to 40 percent) has been demonstrated using low excess air firing and staged
combustion (see section 1.4 for a discussion of these techniques); it is not yet known howevci, whether these
techniques can be continuously employed on lignite combustion units without incurring operational problems.
Sulfur oxides reduction (up to 50 percent) and some particulate control can be achieved through the use of high
sodium lignite. This is not generally considered a desirable practice, however, because of the increased ash fouling
that may result.
Emission factors for lignite combustion are presented in Table 1.7-1.
Table 1.7-1. EMISSIONS FROM LIGNITE COMBUSTION WITHOUT CONTROL EQUIPMENT3
EMISSION FACTOR RATING: B
Pollutant
Particulateb
Sulfur oxides6
Nitrogen
oxidesf
Hydrocarbons'
Carbon
monoxide1
Type of boiler
Pulverized-coal
Ib/ton
7.0AC
SOS
14(8)3,h
<1.0
1.0
kg/MT
3.5AC
15S
7(4)9,h
<0.5
0.5
Cyclone
Ib/ton
6A
305
17
<1.0
1.0
I kg/MT
3A
15S
8.5
<0.5
0.5
Spreaker stoker
Ib/ton
7.0Ad
305
6
1.0
2
kg/MT
3.5Ad
155
3
0.5
1
Other stokers
Ib/ton
3.0A
30S
6
1.0
2
kg/MT
1.5A
155
3
0.5
1
aAII emission factors are expressed in terms of pounds Of pollutant per ton (kilograms of pollutant per metric ton) of lignite burned,
wet basis (35 to 40 percent moisture, by weight).
'-'A is the ash content of the lignite by weight, wet basis Factors based on References 5 and 6
cThis factor is based on data for dry-bottom, pulvenzed-coal-fired units only. It is expected that this factor would be lower for wet-
bottom units.
d Limited data preclude any determination of the effect of flyash reinjectiort. It is expected that particulate emissions would be
greater when reinjection is employed.
eS is the sulfur content of the lignite by weight, wet basis. For a high sodium-ash lignite (Na2O > 8 percent) use 17S Ib/ton (8.5S
kg/MT); for a low sodium-ash lignite {Na2O < 2 percent), use 35S Ib/ton (1 7.5S kg/MT). For intermediate sodium-ash lignite, or
when the sodium-ash content is unknown, use 30S Ib/ton (15S kg/MT)). Factors based on References 2, 5, and 6
^Expressed as NO2- Factors based on References 2, 3, 5, 7, and 9.
gUse 14 Ib/ton (7 kg/MT) for front-wall-fired and horizontally opposed wall-fired units and 8 Ib/ton (4 kg/MT) for tangentially
fired units.
hfMitrogen oxide emissions may be reduced by 20 to 40 percent with low excess air firing and/or staged combustion in front-fired
and opposed-wall-fired units and cyclones
'These factors are based on the similarity of lignite combustion to bituminous coal combustion and on limited data in Reference 7.
References for Section 1.7
1. Kirk-Othmer Encyclopedia of Chemical Technology. 2nd Ed. Vol. 12. New York, John Wiley and Sons, 1967.
p. 381-413.
2. Gronhovd, G. H. et al. Some Studies on Stack Emissions from Lignite-Fired Powerplants. (Presented at the
1973 Lignite Symposium. Grand Forks, North Dakota. May 9-10, 1973.)
3. Study to Support Standards of Performance for New Lignite-Fired Steam Generators. Summary Report.
Arthur D. Little, Inc., Cambridge, Massachusetts. Prepared for U.S. Environmental Protection Agency,
Research Triangle Park, N.C. under contract No. 68-02-1332. July 1974.
1.7-2
EMISSION FACTORS
12/75
-------
4. 1965 Keystone Coal Buyers Manual. New York, McGraw-Hill, Inc., 1965. p. 364-365.
5. Source test data on lignite-fired power plants. Supplied by North Dakota State Department of Health,
Bismark, N.D. December 1973.
6. Gronhovd, G.H. et al. Comparison of Ash Fouling Tendencies of High and Low-Sodium Lignite from a North
Dakota Mine. In: Proceedings of the American Power Conference. Vol. XXVIII. 1966. p. 632-642.
7. Crawford, A. R. et al. Field Testing: Application of Combustion Modifications to Control NOX Emissions
from Utility Boilers. Exxon Research and Engineering Co., Linden, N.J. Prepared for U.S. Environmental
Protection Agency, Research Triangle Park, N.C. under Contract No. 68-02-0227. Publication Number
EPA-650/2-74-066. June 1974.
8. Engelbrecht, H. L. Electrostatic Precipitators in Thermal Power Stations Using Low Grade Coal. (Presented at
28th Annual Meeting of the American Power Conference. April 26-28, 1966.)
9. Source test data from U.S. Environmental Protection Agency. Office of Air Quality Planning and Standards,
Research Triangle Park, N.C. 1974.
12/75 External Combustion Sources 1.7-3
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1.8 BAGASSE COMBUSTION IN SUGAR MILLS by Tom Lahre
1.8.1 General1
Bagasse is the fibrous residue from sugar cane that has been processed in a sugar mill. (See Section
6.12 for a brief general description of sugar cane processing.) It is fired in boilers to eliminate a large
solid waste disposal problem and to produce steam and electricity to meet the mill's power require-
ments. Bagasse represents about 30 percent of the weight of the raw sugar cane. Because of the high
moisture content (usually at least 50 percent, by weight) a typical heating value of wet bagasse will
range from 3000 to 4000 Btu/lb (1660 to 2220 kcal/kg). Fuel oil may be fired with bagasse when the
mill's power requirements cannot be met by burning only bagasse or when bagasse is too wet to support
combustion.
The United States sugar industry is located in Florida, Louisiana, Hawaii, Texas, and Puerto Rico.
Except in Hawaii, where raw sugar production takes place year round, sugar mills operate seasonally,
from 2 to 5 months per year.
Bagasse is commonly fired in boilers employing either a solid hearth or traveling grate. In the for-
mer, bagasse is gravity fed through chutes and forms a pile of burning fibers. The burning occurs on
the surface of the pile with combustion air supplied through primary and secondary ports located in
the furnace walls. This kind of boiler is common in older mills in the sugar cane industry. Newer boil-
ers, on the other hand, may employ traveling-grate stokers. Underfire air is used to suspend the ba-
gasse, and overf ired air is supplied to complete combustion. This kind of boiler requires bagasse with a
higher percentage of fines, a moisture content not over 50 percent, and more experienced operating
personnel.
1.8.2 Emissions and Controls1
Particulate is the major pollutant of concern from bagasse boilers. Unless an auxiliary fuel is fired,
few sulfur oxides will be emitted because of the low sulfur content (<0.1 percent, by weight) of ba-
gasse. Some nitrogen oxides are emitted, although the quantities appear to be somewhat lower (on an
equivalent heat input basis) than are emitted from conventional fossil fuel boilers.
Particulate emissions are reduced by the use of multi-cyclones and wet scrubbers. Multi-cyclones
are reportedly 20 to 60 percent efficient on paniculate from bagasse boilers, whereas scrubbers (either
venturi or the spray impingement type) are usually 90 percent or more efficient. Other types of con-
trol equipment have been investigated but have not been found to be practical.
Emission factors for bagasse fired boilers are shown in Table 1.8-1.
4/77 External Combustion Sources 1.8-1
-------
Table 1.8-1. EMISSION FACTORS FOR UNCONTROLLED BAGASSE BOILERS
EMISSION FACTOR RATING: C
Particulatec
Sulfur oxides
Nitrogen oxides6
Emission factors
lb/103lb steam3
4
d
0.3
g/kg steam3
4
d
0.3
Ib/ton bagasse"
16
d
1.2
kg/MT bagasse'5
8
d
0.6
Emission factors are expressed in terms of the amount of steam produced, as most mills do not monitor the
amount of bagasse fired. These factors should be applied only to that fraction of steam resulting from bagasse
combustion. If a significant amount (>25% of total Btu input) of fuel oil is fired with the bagasse, the appropriate
emission factors from Table 1.3-1 should be used to estimate the emission contributions from the fuel oil.
^Emissions are expressed in terms of wet bagasse, containing approximately 50 percent moisture, by weight.
As a rule of thumb, about 2 pounds (2 kg) of steam are produced from 1 pound (1kg) of wet bagasse.
cMulti-cyclones are reportedly 20 to 60 percent efficient on paniculate from bagasse boilers. Wet scrubbers
are capable of effecting 90 or more percent paniculate control. Based on Reference 1.
dSulfur oxide emissions from the firing of bagasse alone would be expected to be negligible as bagasse typically
contains less than 0.1 percent sulfur, bv weight. If fuel oil is fired with bagasse, the appropriate factors from
Table 1.3-1 should be used to estimate sulfur oxide emissions.
e Based on Reference 1.
Reference for Section 1.8
1. Background Document: Bagasse Combustion in Sugar Mills. Prepared by Environmental Science
and Engineering, Inc., Gainesville, Fla., for Environmental Protection Agency under Contract
No. 68-02-1402, Task Order No. 13. Document No. EPA-450/3-77-007. Research Triangle Park, N.C.
October 1976.
1.8-2
EMISSION FACTORS
4/77
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1.9 RESIDENTIAL FIREPLACES by Tom Lahre
1.9.1 General1.2
Fireplaces are utilized mainly in homes, lodges, etc., for supplemental heating and for their aesthet-
ic effect. Wood is most commonly burned in fireplaces; however, coal, compacted wood waste "logs,"
paper, and rubbish may all be burned at times. Fuel is generally added to the fire by hand on an inter-
mittent basis.
Combustion generally takes place on a raised grate or on the floor of the fireplace. Combustion air
is supplied by natural draft, and may be controlled, to some extent, by a damper located in the chim-
ney directly above the firebox. It is common practice for dampers to be left completely open during
the fire, affording little control of the amount of air drawn up the chimney.
Most fireplaces heat a room by radiation, with a significant fraction of the heat released during com-
bustion (estimated at greater than 70 percent) lost in the exhaust gases or through the fireplace walls.
In addition, as with any fuel-burning, space-heating device, some of the resulting heat energy must go
toward warming the air that infiltrates into the residence to make up for the air drawn up the chimney.
The net effect is that fireplaces are extremely inefficient heating devices. Indeed, in cases where com-
bustion is poor, where the outside air is cold, or where the fire is allowed to smolder (thus drawing air
into a residence without producing apreciable radiant heat energy) a net heat loss may occur in a resi-
dence due to the use of a fireplace. Fireplace efficiency may be improved by a number of devices that
either reduce the excess air rate or transfer some of the heat back into the residence that is normally
lost in the exhaust gases or through the fireplace walls.
1.9.2 Emissions1)2
The major pollutants of concern from fireplaces are unburnt combustibles-carbon monoxide and
smoke. Significant quantities of these pollutants are produced because fireplaces are grossly ineffi-
cient combustion devices due to high, uncontrolled excess air rates, low combustion temperatures, and
the absence of any sort of secondary combustion. The last of these is especially important when burn-
ing wood because of its typically high (80 percent, on a dry weight basis)3 volatile matter content.
Because most wood contains negligible sulfur, very few sulfur oxides are emitted. Sulfur oxides will
be produced, of course, when coal or other sulfur-bearing fuels are burned. Nitrogen oxide emissions
from fireplaces are expected to be negligible because of the low combustion temperatures involved.
Emission factors for wood and coal combustion in residential fireplaces are given in Table 1.9-1.
4/77 External Combustion Sources 1.9-1
-------
Table 1.9-1. EMISSION FACTORS FOR RESIDENTIAL FIREPLACES
EMISSION FACTOR RATING: C
Pollutant
Particulate
Sulfur oxides
Nitrogen oxides
Hydrocarbons
Carbon monoxide
Wood
Ib/ton
2Qb
Od
If
59
12Qh
kg/MT
1Qb
Od
0.5*
2.59
60h
Coal3
Ib/ton
3QC
36Se
3
20
90
kg/MT
15C
36Se
1.5
10
45
All coal emission factors, except paniculate, are based on data in Table 1.1-2
of Section 1.1 for hand-fired units.
This includes condensable paniculate. Only about 30 percent of this is filter-
able paniculate as determined by EPA Method 5 (front-half catch). Based
on limited data from Reference 1.
GThis includes condensable paniculate. About 50 percent of this is filterable
paniculate as determined by EPA Method 5 (front-half catchk4 Based on
limited data from Reference 1.
Based on negligible sulfur content in most wood.3
e'S is the sulfur content, on a weight percent basis, of the coal.
fjBased on data in Table 2.3-1 in Section 2.3 for wood waste combustion in
jconical burners.
9 Nonmethane volatile hydrocarbons. Based on limited data from Reference 1.
h Based on limited data from Reference 1.
References for Section 1.9
1. Snowden, W.D., et al. Source Sampling Residential Fireplaces for Emission Factor Development.
Valentine, Fisher and Tomlinson. Seattle, Washington. Prepared for Environmental Protection
Agency, Research Triangle Park, N.C., under Contract 68-02-1992. Publication No. EPA-450/3-
76-010. November 1975.
2. Snowden, W.D., and I. J. Primlani. Atmospheric Emissions From Residential Space Heating. Pre-
sented at the Pacific Northwest International Section of the Air Pollution Control Association
Annual Meeting. Boise, Idaho. November 1974.
3. Kreisinger, Henry. Combustion of Wood-Waste Fuels. Mechanical Engineering. .61:115, February
1939.
4. Title 40 - Protection of Environment. Part 60: Standards of Performance for New Stationary
Sources. Method 5 - Detemination of Emission from Stationary Sources. Federal Register. 36
(247): 24888-24890, December 23, 1971.
1.9-2
EMISSION FACTORS
4/77
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2. SOLID WASTE DISPOSAL
Revised by Robert Rosensteel
As defined in the Solid Waste Disposal Act of 1965, the term "solid waste" means garbage, refuse, and other
discarded solid materials, including solid-waste materials resulting from industrial, commercial, and agricultural
operations, and from community activities. It includes both combustibles and noncombustibles.
Solid wastes may be classified into four general categories: urban, industrial, mineral, and agricultural.
Although urban wastes represent only a relatively small part of the total solid wastes produced, this category has
a large potential for air pollution since in heavily populated areas solid waste is often burned to reduce the bulk
of material requiring final disposal.1 The following discussion will be limited to the urban and industrial waste
categories.
An average of 5.5 pounds (2.5 kilograms) of urban refuse and garbage is collected per capita per day in the
United States.2 This figure does not include uncollected urban and industrial wastes that are disposed of by other
means. Together, uncollected urban and industrial wastes contribute at least 4.5 pounds (2.0 kilograms) per
capita per day. The total gives a conservative per capita generation rate of 10 pounds (4.5 kilograms) per day of
urban and industrial wastes. Approximately 50 percent of all the urban and industrial waste generated in the
United States is burned, using a wide variety of combustion methods with both enclosed and open
burning3. Atmospheric emissions, both gaseous and particulate, result from refuse disposal operations that use
combustion to reduce the quantity of refuse. Emissions from these combustion processes cover a wide range
because of their dependence upon the refuse burned, the method of combustion or incineration, and other
factors. Because of the large number of variables involved, it is not possible, in general, to delineate when a higher
or lower emission factor, or an intermediate value should be used. For this reason, an average emission factor has
been presented.
References
1. Solid Waste - It Will Not Go Away. League of Women Voters of the United States. Publication Number 675.
April 1971.
2. Black, R.J., H.L. Hickman, Jr., AJ. Klee, A.J. Muchick, and R.D. Vaughan. The National Solid Waste
Survey: An Interim Report. Public Health Service, Environmental Control Administration. Rockville, Md.
1968.
3. Nationwide Inventory of Air Pollutant Emissions, 1968. U.S. DHEW, PHS, EHS, National Air Pollution
Control Administration. Raleigh, N.C. Publication Number AP-73. August 1970.
4/73 2.1-1
-------
2.1 REFUSE INCINERATION Revised by Robert Rosensteel
2.1.1 Process Description1 "4
The most common types of incinerators consist of a refractory-lined chamber with a grate upon which refuse
is burned. In some newer incinerators water-walled furnaces are used. Combustion products are formed by
heating and burning of refuse on the grate. In most cases, since insufficient underfire (undergrate) air is provided
to enable complete combustion, additional over-fire air is admitted above the burning waste to promote complete
gas-phase combustion. In multiple-chamber incinerators, gases from the primary chamber flow to a small
secondary mixing chamber where more air is admitted, and more complete oxidation occurs. As much as 300
percent excess air may be supplied in order to promote oxidation of combustibles. Auxiliary burners are
sometimes installed in the mixing chamber to increase the combustion temperature. Many small-size incinerators
are single-chamber units in which gases are vented from the primary combustion chamber directly into the
exhaust stack. Single-chamber incinerators of this type do not meet modern air pollution codes.
2.1.2 Definitions of Incinerator Categories1
No exact definitions of incinerator size categories exist, but for this report the following general categories and
descriptions have been selected:
1. Municipal incinerators — Multiple-chamber units often have capacities greater than 50 tons (45.3 MT)
per day and are usually equipped with automatic charging mechanisms, temperature controls, and
movable grate systems. Municipal incinerators are also usually equipped with some type of particulate
control device, such as a spray chamber or electrostatic precipitator.
2. Industrial!commercial incinerators — The capacities of these units cover a wide range, generally between
50 and 4,000 pounds (22.7 and 1,800 kilograms) per hour. Of either single- or multiple-chamber design,
these units are often manually charged and intermittently operated. Some industrial incinerators are
similar to municipal incinerators in size and design. Better designed emission control systems include
gas-fired afterburners or scrubbing, or both.
3. Trench Incinerators — A trench incinerator is designed for the combustion of wastes having relatively high
heat content and low ash content. The design of the unit is simple: a U-shaped combustion chamber is
formed by the sides and bottom of the pit and air is supplied from nozzles along the top of the pit. The
nozzles are directed at an angle below the horizontal to provide a curtain of air across the top of the pit
and to provide air for combustion in the pit. The trench incinerator is not as efficient for burning wastes
as the municipal multiple-chamber unit, except where careful precautions are taken to use it for disposal
of low-ash, high-heat-content refuse, and where special attention is paid to proper operation. Low
construction and operating costs have resulted in the use of this incinerator to dispose of materials other
than those for which it was originally designed. Emission factors for trench incinerators used to burn
three such materials^ are included in Table 2.1-1.
4. Domestic incinerators — This category includes incinerators marketed for residential use. Fairly simple in
design, they may have single or multiple chambers and usually are equipped with an auxiliary burner to
aid combustion.
2-1-2 EMISSION FACTORS 4/73
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Solid Waste Disposal
2.1-3
-------
5. Flue-fed incinerators - These units, commonly found in large apartment houses, are characterized by
the charging method of dropping refuse down the incinerator flue and into the combustion chamber.
Modified flue-fed incinerators utilize afterburners and draft controls to improve combustion efficiency
and reduce emissions.
6. Pathological incinerators - These are incinerators used to dispose of animal remains and other organic
material of high moisture content. Generally, these units are in a size range of 50 to 100 pounds (22.7 to
45.4 kilograms) per hour. Wastes are burned on a hearth in the combustion chamber. The units are
equipped with combustion controls and afterburners to ensure good combustion and minimal emissions.
7. Controlled air incinerators — These units operate on a controlled combustion principle in which the
waste is burned in the absence of sufficient oxygen for complete combustion in the main chamber. This
process generates a highly combustible gas mixture that is then burned with excess air in a secondary
chamber, resulting in efficient combustion. These units are usually equipped with automatic charging
mechanisms and are characterized by the high effluent temperatures reached at the exit of the
incinerators.
2.1.3 Emissions and Controls1
Operating conditions, refuse composition, and basic incinerator design have a pronounced effect on
emissions. The manner in which air is supplied to the combustion chamber or chambers has, among all the
parameters, the greatest effect on the quantity of particulate emissions. Air may be introduced from beneath the
chamber, from the side, or from the top of the combustion area. As underfire air is increased, an increase in
fly-ash emissions occurs. Erratic refuse charging causes a disruption of the combustion bed and a subsequent
release of large quantities of particulates. Large quantities of uncombusted particulate matter and carbon
monoxide are also emitted for an extended period after charging of batch-fed units because of interruptions in
the combustion process. In continuously fed units, furnace particulate emissions are strongly dependent upon
grate type. The use of rotary kiln and reciprocating grates results in higher particulate emissions than the use of
rocking or traveling grates.14 Emissions of oxides of sulfur are dependent on the sulfur content of the refuse.
Carbon monoxide and unburned hydrocarbon emissions may be significant and are caused by poor combustion
resulting from improper incinerator design or operating conditions. Nitrogen oxide emissions increase with an
increase in the temperature of the combustion zone, an increase in the residence time in the combustion zone
before quenching, and an increase in the excess air rates to the point where dilution cooling overcomes the effect
of increased oxygen concentration.14
Table 2.1-2 lists the relative collection efficiencies of particulate control equipment used for municipal
incinerators. This control equipment has little effect on gaseous emissions. Table 2.1-1 summarizes the
uncontrolled emission factors for the various types of incinerators previously discussed.
Table 2.1-2. COLLECTION EFFICIENCIES FOR VARIOUS TYPES OF
MUNICIPAL INCINERATION PARTICULATE CONTROL SYSTEMS3
Type of system
Settling chamber
Settling chamber and water spray
Wetted baffles
Mechanical collector
Scrubber
Electrostatic precipitator
Fabric filter
Efficiency, %
0 to 30
30 to 60
60
30 to 80
80 to 95
90 to 96
97 to 99
References 3, 5, 6, and 17 through 21.
2.1-4 EMISSION FACTORS 4/73
-------
References for Section 2.1
1. Air Pollutant Emission Factors. Final Report. Resources Research Incorporated, Reston, Virginia. Prepared
for National Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119.
April 1970.
2. Control Techniques for Carbon Monoxide Emissions from Stationary Sources. U.S. DHEW, PHS, EHS,
National Air Pollution Control Administration. Washington, B.C. Publication Number AP-65. March 1970.
3. Danielson, J.A. (ed.). Air Pollution Engineering Manual. U.S. DHEW, PHS National Center for Air Pollution
Control. Cincinnati, Ohio. Publication Number 999-AP-40. 1967. p. 413-503.
„ 4. De Marco, J. et al. Incinerator Guidelines 1969. U.S. DHEW, Public Health Service. Cincinnati, Ohio.
SW-13TS. 1969. p. 176.
5. Kanter, C. V., R. G. Lunche, and A.P. Fururich. Techniques for Testing for Air Contaminants from
* Combustion Sources. J. Air Pol. Control Assoc. 6(4): 191-199. February 1957.
6. Jens. W. and F.R. Rehm. Municipal Incineration and Air Pollution Control. 1966 National Incinerator
Conference, American Society of Mechnical Engineers. New York, May 1966.
7. Burkle, J.O., J. A. Dorsey, and B. T. Riley. The Effects of Operating Variables and Refuse Types on
Emissions from a Pilot-Scale Trench Incinerator. Proceedings of the 1968 Incinerator Conference, American
Society of Mechanical Engineers. New York. May 1968. p. 34-41.
8. Fernandas, J. H. Incinerator Air Pollution Control. Proceedings of 1968 National Incinerator Conference,
American Society of Mechanical Engineers. New York. May 1968. p. 111.
9. Unpublished data on incinerator testing. U.S. DHEW, PHS, EHS, National Air Pollution Control
Administration. Durham, N.C. 1970.
10. Stear, J. L. Municipal Incineration: A Review of Literature. Environmental Protection Agency, Office of Air
Programs. Research Triangle Park, N.C. OAP Publication Number AP-79. June 1971.
11. Kaiser, E.R. et al. Modifications to Reduce Emissions from a Flue-fed Incinerator. New York University.
College of Engineering. Report Number 552.2. June 1959. p. 40 and 49.
12. Unpublished data on incinerator emissions. U.S. DHEW, PHS, Bureau of Solid Waste Management.
Cincinnati, Ohio. 1969.
13. Kaiser, E.R. Refuse Reduction Processes in Proceedings of Surgeon General's Conference on Solid Waste
Management. Public Health Service. Washington, D.C. PHS Report Number 1729. July 10-20, 1967.
14. Nissen, Walter R. Systems Study of Air Pollution from Municipal Incineration. Arthur D. Little, Inc.
Cambridge, Mass. Prepared for National Air Pollution Control Administration, Durham, N.C., under Contract
Number CPA-22-69-23. March 1970.
4/73 Solid Waste Disposal 2.1-5
-------
15. Unpublished source test data on incinerators. Resources Research, Incorporated. Reston, Virginia.
1966-1969.
16. Communication between Resources Research, Incorporated, Reston, Virginia, and Maryland State
Department of Health, Division of Air Quality Control, Baltimore, Md. 1969.
17. Rehm, F.R. Incinerator Testing and Test Results. J. Air Pol. Control Assoc. 6:199-204. February 1957.
18. Stenburg, R.L. et al. Field Evaluation of Combustion Air Effects on Atmospheric Emissions from Municipal
Incinerations. J. Air Pol. Control Assoc. 72:83-89. February 1962.
19. Smauder, E.E. Problems of Municipal Incineration. (Presented at First Meeting of Air Pollution Control
Association, West Coast Section, Los Angeles, California. March 1957.)
20. Gerstle, R. W. Unpublished data: revision of emission factors based on recent stack tests. U.S. DHEW, PHS,
National Center for Air Pollution Control. Cincinnati, Ohio. 1967.
21. A Field Study of Performance of Three Municipal Incinerators. University of California, Berkeley, Technical
Bulletin. 6:41, November 1957.
2.1-6 EMISSION FACTORS 4/73
-------
2.2 AUTOMOBILE BODY INCINERATION
Revised by Robert Rosensteel
2.2.1 Process Description
Auto incinerators consist of a single primary combustion chamber in which one or several partially stripped
cars are burned. (Tires are removed.) Approximately 30 to 40 minutes is required to burn two bodies
simultaneously.2 As many as 50 cars per day can be burned in this batch-type operation, depending on the
capacity of the incinerator. Continuous operations in which cars are placed on a conveyor belt and passed
through a tunnel-type incinerator have capacities of more than 50 cars per 8-hour day.
2.2.2 Emissions and Controls'
Both the degree of combustion as determined by the incinerator design and the amount of combustible
material left on the car greatly affect emissions. Temperatures on the order of 1200°F (650°C) are reached during
auto body incineration.2 This relatively low combustion temperature is a result of the large incinerator volume
needed to contain the bodies as compared with the small quantity of combustible material. The use of overfire air
jets in the primary combustion chamber increases combustion efficiency by providing air and increased
turbulence.
In an attempt to reduce the various air pollutants produced by this method of burning, some auto incinerators
are equipped with emission control devices. Afterburners and low-voltage electrostatic precipitators have been
used to reduce particulate emissions; the former also reduces some of the gaseous emissions.3'4 When
afterburners are used to control emissions, the temperature in the secondary combustion chamber should be at
least 1500°F (815°C). Lower temperatures result in higher emissions. Emission factors for auto body incinerators
are presented in Table 2.2-1.
Table 2.2-1. EMISSION FACTORS FOR AUTO BODY INCINERATION3
EMISSION FACTOR RATING: B
Pollutants
Particulatesb
Carbon monoxide0
Hydrocarbons (CH4)C
Nitrogen oxides (NO2)d
Aldehydes (HCOH)d
Organic acids (acetic)d
Uncontrolled
Ib/car
2
2.5
0.5
0.1
0.2
0.21
kg/car
0.9
1.1
0.23
0.05
0.09
0.10
With afterburner
Ib/car
1.5
Neg
Neg
0.02
0.06
0.07
kg/car
0.68
Neg
Neg
0.01
0.03
0.03
aBased on 250 Ib (113 kg) of combustible material on stripped car body.
'-'References 2 and 4.
cBased on data for open burning and References 2 and 5.
dReference 3
4/73
Solid Waste Disposal
2.2-1
-------
References for Section 2.2
1. Air Pollutant Emission Factors. Final Report. Resources Research Inc. Reston, Va. Prepared for National Air
Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Kaiser, E.R. and J. Tolcias. Smokeless Burning of Automobile Bodies. J. Air Pol. Control Assoc. 72:64-73,
February 1962.
3. Alpiser, P.M. Air Pollution from Disposal of Junked Autos. Air Engineering. 10:18-22, November 1968.
4. Private communication with D.F. Walters, U.S. DHEW, PHS, Division of Air Pollution. Cincinnati, Ohio. July
19, 1963.
5. Gerstle, R.W. and D.A. Kemnitz. Atmospheric Emissions from Open Burning. J. Air Pol. Control Assoc.
77:324-327. May 1967.
2.2-2 EMISSION FACTORS 4/73
-------
2.3 CONICAL BURNERS
2.3.1 Process Description1
Conical burners are generally a truncated metal cone with a screened top vent. The charge is placed on a
raised grate by either conveyor or bulldozer; however, the use of a conveyor results in more efficient burning. No
supplemental fuel is used, but combustion air is often supplemented by underfire air blown into the chamber
below the grate and by overfire air introduced through peripheral openings in the shell.
2.3.2 Emissions and Controls
The quantities and types of pollutants released from conical burners are dependent on the composition and
moisture content of the charged material, control of combustion air, type of charging system used, and the
condition in which the incinerator is maintained. The most critical of these factors seems to be the level of
maintenance on the incinerators. It is not uncommon for conical burners to have missing doors and numerous
holes in the shell, resulting in excessive combustion air, low temperatures, and, therefore, high emission rates of
combustible pollutants.2
Particulate control systems have been adapted to conical burners with some success. These control systems
include water curtains (wet caps) and water scrubbers. Emission factors for conical burners are shown in Table
2.3-1.
4/73 Solid Waste Disposal 2.3-1
-------
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EMISSION FACTORS
4/73
-------
References for Section 2.3
1. Air Pollutant Emission Factors. Final Report. Resources Research Inc. Reston, Va. Prepared for National Air
Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Kreichelt, I.E. Air Pollution Aspects of Teepee Burners. U.S. DHEW, PHS, Division of Air Pollution.
Cincinnati, Ohio. PHS Publication Number 999-AP-28. September 1966.
3. Magill, P.L. and R.W. Benoliel. Air Pollution in Los Angeles County: Contribution of Industrial Products.
Ind. Eng. Chem. 44:1347-1352, June 1952.
4. Private communication with Public Health Service, Bureau of Solid Waste Management, Cincinnati, Ohio.
October 31, 1969.
5. Anderson, D.M., J. Lieben, and V.H. Sussman. Pure Air for Pennsylvania. Pennsylvania State Department of
Health, Harrisburg. November 1961. p.98.
6. Boubel, R.W. et al. Wood Waste Disposal and Utilization. Engineering Experiment Station, Oregon State
University, Corvallis. Bulletin Number 39. June 1958. p.57.
7. Netzley, A.B. and J.E. Williamson. Multiple Chamber Incinerators for Burning Wood Waste. In: Air Pollution
Engineering Manual, Danielson, J.A. (ed.). U.S. DHEW, PHS, National Center for Air Pollution Control.
Cincinnati, Ohio. PHS Publication Number 999-AP-40. 1967. p.436-445.
8. Droege, H. and G. Lee. The Use of Gas Sampling and Analysis for the Evaluation of Teepee Burners. Bureau
of Air Sanitation, California Department of Public Health. (Presented at the 7th Conference on Methods in
Air Pollution Studies, Los Angeles. January 1965.)
9. Boubel R.W. Particulate Emissions from Sawmill Waste Burners. Engineering Experiment Station, Oregon
State University, Corvallis. Bulletin Number 42. August 1968. p.7,8.
4/73 Solid Waste Disposal 2.3-3
-------
-------
2.4 OPEN BURNING
2.4.1 General1
revised by Tom Lahre
and Pam Canova
Open burning can be done in open drums or baskets, in fields and yards, and in large open dumps
or pits. Materials commonly disposed of in this manner are municipal waste, auto body components,
landscape refuse, agricultural field refuse, wood refuse, bulky industrial refuse, and leaves.
2.4.2 Emissions1-19
, Ground-level open burning is affected by many variables including wind, ambient temperature,
composition and moisture content of the debris burned, and compactness of the pile. In general, the
relatively low temperatures associated with open burning increase the emission of particulates, car-
bon monoxide, and hydrocarbons and suppress the emission of nitrogen oxides. Sulfur oxide emissions
are a direct function of the sulfur content of the refuse. Emission factors are presented in Table 2.4-1
for the open burning of municipal refuse and automobile components.
Table 2.4-1. EMISSION FACTORS FOR OPEN BURNING OF NONAGRICULTURAL MATERIAL
EMISSION FACTOR RATING: B
Municipal refuse
Ib/ton
kg/MT
Automobile
h c
components
Ib/ton
kg/MT
Particulates
16
8
100
50
Sulfur
oxides
1
0.5
Neg.
Neg.
Carbon
monoxide
85
42
125
62
Hydrocarbons
(CH4)
30
15
30
15
Nitrogen oxides
6
3
4
2
References 2 through 6.
Upholstery, belts, hoses, and tires burned in common.
"-Reference 2.
Emissions from agricultural refuse burning are dependent mainly on the moisture content of the
refuse and, in the case of the field crops, on whether the refuse is burned in a headfire or a backfire.
(Headf ires are started at the upwind side of a field and allowed to progress in the direction of the wind,
whereas backfires are started at the downwind edge and forced to progress in a direction opposing the
wind.) Other variables such as fuel loading (how much refuse material is burned per unit of land area)
and how the refuse is arranged (that is, in piles, rows, or spread out) are also important in certain
instances. Emission factors for open agricultural burning are presented in Table 2.4-2 as a function of
refuse type and also, in certin instances, as a function of burning techniques and/or moisture content
when these variables are known to significantly affect emissions. Table 2.4-2 also presents typical fuel
loading values associated with each type of refuse. These values can be used, along with the correspond-
ing emission factors, to estimate emissions from certain categories of agricultural burning when the
specific fuel loadings for a given area are not known.
Emissions from leaf burning are dependent upon the moisture content, density, and ignition loca-
tion of the leaf piles. Increasing the moisture content of the leaves generally increases the amount of
carbon monoxide, hydrocarbon, and particulate emissions. Increasing the density of the piles in-
creases the amount of hydrocarbon and particulate emissions, but has a variable effect on carbon
4/77
Solid Waste Disposal
2.4-1
-------
Table 2.4-2. EMISSION FACTORS AND FUEL LOADING FACTORS FOR OPEN BURNING
OF AGRICULTURAL MATERIALS3
EMISSION FACTOR RATING: B
Refuse category
Field crops0
Unspecified
Burning technique
not significant0"
Asparagus6
Barley
Corn
Cotton
Grasses
Pineapple'
Rice9
Safflower
Sorghum
Sugar canen
Headfire burning1
Alfalfa
Bean (red)
Hay (wild)
Oats
Pea
Wheat
Backfire burning'
Alfalfa
Bean (red), pea
Hay (wild)
Oats
Wheat
Vine crops
Weeds
Unspecified
Russian thistle
(tumbleweed)
Tules (wild reeds)
Orchard cropsc-*''
Unspecified
Almond
Apple
Apricot
Avocado
Cherry
Citrus (orange,
lemon)
Date palm
Fig
Emission factors
Particulateb
Ib/ton
21
40
22
14
8
16
8
9
18
18
7
45
43
32
44
31
22
29
14
17
21
13
5
15
22
5
6
6
4
6
21
8
6
10
7
^kg/MT
11
20
11
7
4
8
4
4
9
9
4
23
22
16
22
16
11
14
7
8
11
6
3
8
11
3
3
3
2
3
10
4
3
5
4
Carbon
monoxide
Ib/ton
117
150
157
108
176
101
112
83
144
77
71
106
186
139
137
147
128
119
148
150
136
108
51
. 85
309
34
52
46
42
49
116
44
81
56
57
kg/MT
58
75
78
54
88
50
56
41
72
38
35
53
93
70
68
74
64
60
72
75
68
54
26
42
154
17
26
23
21
24
58
22
40
28
28
Hydrocarbons
(asC6H14)
Ib/ton
23
85
19
16
6
19
8
10
26
9
10
36
46
22
33
38
17
37
25
17
18
11
7
12
2
27
10
8
4
8
32
10
12
7
10
kg/MT
12
42
10
8
3
10
4
5
13
4
5
18
23
11
16
19
9
18
12
8
9
6
4
6
1
14
5
4
2
4
16
5
6
4
5
Fuel loading factors
(waste production)
ton/acre
2.0
1.5
1.7
4.2
1.7
3.0
1.3
2.9
11.0
0.8
2.5
1.0
1.6
2.5
1.9
0.8
2.5
1.0
1.6
1.9
2.5
3.2
0.1
1.6
1.6
2.3
1.8
1.5
1.0
1.0
1.0
2.2
MT/hectare
4.5
3.4
3.8
9.4
3.8
6.7
2.9
6.5
24.0
1.8
5.6
2.2
3.6
5.6
4.3
1.8
5.6
2.2
3.6
4.3
5.6
7.2
0.2
3.6
3.6
5.2
4.0
3.4
2.2
2.2
2.2
4.9
2.4-2
EMISSION FACTORS
4/77
-------
Table 2.4-2 (continued). EMISSION FACTORS AND FUEL LOADING FACTORS FOR OPEN BURNING
OF AGRICULTURAL MATERIALS3
EMISSION'FACTOR RATING: B
Refuse category
Orchard cropsc-k''
(continued)
Nectarine
Olive
Peach
Pear
Prune
Walnut
Forest residues
Unspecified™1
Hemlock, Douglas
fir, cedarn
Ponderosa pme°
Emission factors
Particulateb
Ib/ton
4
12
6
9
3
6
17
4
12
kg/MT
2
6
3
4
2
3
8
2
6
Carbon
monoxide
Ib/ton
33
114
42
57
42
47
140
90
195
kg/MT
16
57
21
28
21
24
70
45
98
Hydrocarbons
(asC6H14)
Ib/ton
4
18
5
9
3
8
24
5
14
kg/MT
2
9
2
4
2
4
12
2
7
Fuel loading factors
(waste production)
ton/acre
2.0
1.2
2.5
2.6
1.2
1.2
70
MT/hectare
4.5
2.7
5.6
5.8
2.7
2-7
157
aFactors expressed as weight of pollutant emitted per weight of refuse material burned.
"Particulate matter from most agricultural refuse burning has been found to be in the submicrometer size range.1 2
""References 12 and 13 for emission factors; Reference 14 for fuel loading factors.
For these refuse materials, no significant difference exists between emissions resulting from headfiring or backfiring.
^hese factors represent emissions under typical high moisture conditions. If ferns are dried to less than 15 percent
moisture, paniculate emissions will be reduced by 30 percent, CO emission by 23 percent, and HC by 74 percent.
'When pineapple is allowed to dry to less than 20 percent moisture, as it usually is, the firing technique is not important.
When headfired above 20 percent moisture, paniculate emission will increase to 23 Ib/ton (1 1 .5 kg/MT) and HC will
increase to 12 Ib/ton (6 kg/MT). See Reference 11.
SThis factor is for dry (<1 5 percent moisture) rice straw. If rice straw is burned at higher moisture levels, paniculate
emission will increase to 29 Ib/ton (14.5 kg/MT), CO emission to 161 Ib/ton (80.5 kg/MT), and HC emission to 21
Ib/ton (10.5 kg/MT).
See Section 6.12 for discussion of sugar cane burning.
'See accompanying text for definition of headfiring.
'See accompanying text for definition of backfiring. This category, for emission estimation purposes, includes another
technique used occasionally for limiting emissions, called into-the-wind striplighting, which involves lighting fields in
strips into the wind at 100-200 m (300-600 ft) intervals.
Orchard prumngs are usually burned in piles. No significant difference in emission results from burning a "cold pile"
as opposed to using a roll-on technique, where primings are bulldozed onto a bed of embers from a preceding fire.
'if orchard removal is the purpose of a burn, 30 ton/acre (66 MT/hectare) of waste will be produced.
mReference 10. Nitrogen oxide emissions estimated at 4 Ib/ton (2 kg/MT).
"Reference 15
°Reference 16.
monoxide emissions. Arranging the leaves in conical piles and igniting around the periphery of the bot-
tom proves to be the least desirable method of burning. Igniting a single spot on the top of the pile
decreases the hydrocarbon and particulate emissions. Carbon monoxide emissions with top ignition
decrease if moisture content is high but increase if moisture content is low. Particulate, hydrocarbon,
and carbon monoxide emissions from windrow ignition (piling the leaves into a long row and igniting
one end, allowing it to burn toward the other end) are intermediate between top and bottom ignition.
Emission factors for leaf burning are presented in Table 2.4-3.
For more detailed information on this subject, the reader should consult the references cited at the
end of this section.
4/77
Solid Waste Disposal
2.4-3
-------
Table 2.4-3. EMISSION FACTORS FOR LEAF BURNING18.
EMISSION FACTOR RATING: B
19
Leaf species
Black Ash
Modesto Ash
White Ash
Catalpa
Horse Chestnut
Cottonwood
American Elm
Eucalyptus
Sweet Gum
Black Locust
Magnolia
Silver Maple
American Sycamore
California Sycamore
Tulip
Red Oak
Sugar Maple
Unspecified
Particulatea-b
Ib/ton
36
32
43
17
54
38
26
36
33
70
13
66
15
10
20
92
53
38
kg/MT
18
16
21.5
8.5
27
19
13
18
16.5
35
6.5
33
7.5
5
10
46
26.5
19
Carbon monoxide3
Ib/ton
127
163
113
89
147
90
119
90
140
130
55
102
115
104
77
137
108
112
kg/MT
63.5
81.5
57
44.5
73.5
45
59.5
45
70
65
27.5
51
57.5
52
38.5
68.5
54
56
Hydrocarbons3'0
Ib/ton
41
25
21
15
39
32
29
26
27
62
10
25
8
5
16
34
27
26
kg/MT
20.5
12.5
10.5
7.5
19.5
16
14.5
13
13.5
31
5
12.5
4
2.5
8
.17
13.5
13
aThese factors are an arithmetic average of the results obtained by burning high- and low-moisture content conical piles ignited
either at the top or around the periphery of the bottom. The windrow arrangement was only tested on Modesto Ash, Catalpa,
American Elm, Sweet Gum, Silver Maple, and Tuljp, and the results are included in the averages for these species.
"The majority of particulates are submicron in size.
cTests indicate hydrocarbons consist, on the average, of 42% olefins, 32% methane, 8% acetylene, and 13% other saturates.
References for Section 2.4
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc., Reston, Va. Prepared for
National Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-
69-119. April 1970.
2. Gerstle, R. W. and D. A. Kemnitz. Atmospheric Emissions from Open Burning. J. Air Pol. Control
Assoc. 12:324-327. May 1967.
3. Burkle, J.O., J. A. Dorsey, and B.T. Riley. The Effects of Operating Variables and Refuse Types on
Emissions from a Pilot-Scale Trench Incinerator. In: Proceedings of 1968 Incinerator Confer-
ence, American Society of Mechanical Engineers. New York. May 1968. p. 34-41.
4. Weisburd, M.I. and S.S. Griswold (eds.). Air Pollution Control Field Operations Guide: A Guide
for Inspection and Control. U.S. DREW, PHS, Division of Air Pollution, Washington, D.C. PHS
Publication No. 937. 1962.
2.4-4
EMISSION FACTORS
4/77
-------
5. Unpublished data on estimated major air contaminant emissions. State of New York Department
of Health. Albany. April 1, 1968.
6. Darley, E.F. et al. Contribution of Burning of Agricultural Wastes to Photochemical Air Pollu-
tion. J. Air Pol. Control Assoc. 16:685-690, December 1966.
7. Feldstein, M. et al. The Contribution of the Open Burning of Land Clearing Debris to Air Pollu-
tion. J. Air Pol. Control Assoc. 73:542-545, November 1963.
8. Boubel, R.W., E.F. Darley, and E.A. Schuck. Emissions from Burning Grass Stubble and Straw.
J. Air Pol. Control Assoc. 19:497-500, July 1969.
9. Waste Problems of Agriculture and Forestry. Environ. Sci. and Tech. 2:498, July 1968.
10. Yamate, G. et al. An Inventory of Emissions from Forest Wildfires, Forest Managed Burns, and
Agricultural Burns and Development of Emission Factors for Estimating Atmospheric Emissions
from Forest Fires. (Presented at 68th Annual Meeting Air Pollution Control Association. Boston.
June 1975.)
11. Darley, E.F. Air Pollution Emissions from Burning Sugar Cane and Pineapple from Hawaii.
University of California, Riverside, Calif. Prepared for Environmental Protection Agency, Re-
search Triangle Park, N.C. as amendment to Research Grant No. R800711. August 1974.
12. Darley, E.F. et al. Air Pollution from Forest and Agricultural Burning. California Air Resources
Board Project 2-017-1, University of California. Davis, Calif. California Air Resources Board
Project No. 2-017-1. April 1974.
13. Darley, E.F. Progress Report on Emissions from Agricultural Burning. California Air Resources
Board Project 4-011. University of California, Riverside, Calif. Private communication with per-
mission of Air Resources Board, June 1975.
14. Private communication on estimated waste production from agricultural burning activities. Cal-
ifornia Air Resources Board, Sacramento, Calif. September 1975.
15. Fritschen, L. et al. Flash Fire Atmospheric Pollution. U.S. Department of Agriculture, Washing-
ton, D.C. Service Research Paper PNW-97. 1970.
16. Sandberg, D. V., S.G. Pickford, and E.F. Darley. Emissions from Slash Burning and the Influence
of Flame Retardant Chemicals. J. Air Pol. Control Assoc. 25:278, 1975.
17. Wayne, L.G. and M.L. McQueary. Calculation of Emission Factors for Agricultural Burning
Activities. Pacific Environmental Services, Inc., Santa Monica, Calif. Prepared for Environ-
mental Protection Agency, Research Triangle Park, N.C., under Contract No. 68-02-1004, Task
Order No. 4. Publication No. EPA-450/3-75-087. November 1975.
18. Darley, E.F. Emission Factor Development for Leaf Burning. University of California, Riverside,
Calif. Prepared for Environmental Protection Agency, Research Triangle Park, N.C., under Pur-
chase Order No. 5-02-6876-1. September 1976.
19. Darley, E.F. Evaluation of the Impact of Leaf Burning - Phase I: Emission Factors for Illinois
Leaves. University of California, Riverside, Calif. Prepared for State of Illinois, Institute for En-
vironmental Quality. August 1975.
4/77 Solid Waste Disposal 2.4-5
-------
-------
2.5 SEWAGE SLUDGE INCINERATION By Thomas Lahre
2.5.1 Process Description 1-3
Incineration is becoming an important means of disposal for the increasing amounts of sludge being produced
in sewage treatment plants. Incineration has the advantages of both destroying the organic matter present in
sludge, leaving only an odorless, sterile ash, as well as reducing the solid mass by about 90 percent. Disadvantages
include the remaining, but reduced, waste disposal problem and the potential for air pollution. Sludge inciner-
ation systems usually include a sludge pretreatment stage to thicken and dewater the incoming sludge, an inciner-
ator, and some type of air pollution control equipment (commonly wet scrubbers).
The most prevalent types of incinerators are multiple hearth and fluidized bed units. In multiple hearth
units the sludge enters the top of the furnace where it is first dried by contact with the hot, rising, combustion
gases, and then burned as it moves slowly down through the lower hearths. At the bottom hearth any residual
ash is then removed. In fluidized bed reactors, the combustion takes place in a hot, suspended bed of sand with
much of the ash residue being swept out with the flue gas. Temperatures in a multiple hearth furnace are 600°F
(320°C) in the lower, ash cooling hearth; 1400 to 2000°F (760 to 1100°C) in the central combustion hearths,
and 1000 to 1200°F (540 to 650°C) in the upper, drying hearths. Temperatures in a fluidized bed reactor are
fairly uniform, from 1250 to 1500°F (680 to 820°C). In both types of furnace an auxiliary fuel may be required
either during startup or when the moisture content of the sludge is too high to support combustion.
2.5.2 Emissions and Controls 1.2,4-7
Because of the violent upwards movement of combustion gases with respect to the burning sludge, particu-
lates are the major emissions problem in both multiple hearth and fluidized bed incinerators. Wet scrubbers are
commonly employed for particulate control and can achieve efficiencies ranging from 95 to 99+ percent.
Although dry sludge may contain from 1 to 2 percent sulfur by weight, sulfur oxides are not emitted in signif-
icant amounts when sludge burning is compared with many other combustion processes. Similarly, nitrogen
oxides, because temperatures during incineration do not exceed 1500°F (820°C) in fluidized bed reactors or
1600 to 2000°F (870 to 1100°C) in multiple hearth units, are not formed in great amounts.
Odors can be a problem in multiple hearth systems as unburned volatiles are given off in the upper, drying
hearths, but are readily removed when afterburners are employed. Odors are not generally a problem in fluid-
ized bed units as temperatures are uniformly high enough to provide complete oxidation of the volatile com-
pounds. Odors can also emanate from the pretreatment stages unless the operations are properly enclosed.
Emission factors for sludge incinerators are shown in Table 2.5-1. It should be noted that most sludge incin-
erators operating today employ some type of scrubber.
5/74 Solid Waste Disposal 2.5-1
-------
Table 2.5-1. EMISSION FACTORS FOR SEWAGE SLUDGE INCINERATORS
EMISSION FACTOR RATING: B
Pollutant
Particulatec
Sulfur dioxided
Carbon monoxide6
Nitrogen oxidesd (as N02>
Hydrocarbons'^
Hydrogen chloride gasd
Emissions a
Uncontrolled13
Ib/ton
100
1
Neg
6
1.5
1.5
kg/MT
50
0.5
Neg
3
0.75
0.75
After scrubber
Ib/ton
3
0.8
Neg
5
1
0.3
kg/MT
1.5
0.4
Neg
2.5
0.5
0.15
aUnit weights in terms of dried sludge.
t> Estimated from emission factors after scrubbers.
cReferences 6-9.
dReference 8.
eReferences 6, 8.
References for Section 2.5
1. Calaceto, R. R. Advances in Fly Ash Removal with Gas-Scrubbing Devices. Filtration Engineering. 7(7):12-15,
March 1970.
2. Balakrishnam, S. et al. State of the Art Review on Sludge Incineration Practices. U.S. Department of the
Interior, Federal Water Quality Administration, Washington, D.C. FWQA-WPC Research Series.
3. Canada's Largest Sludge Incinerators Fired Up and Running. Water and Pollution Control. /07(1):20-21, 24,
January 1969.
4. Calaceto, R. R. Sludge Incinerator Fly Ash Controlled by Cyclonic Scrubber. Public Works. 94(2): 113-114,
February 1963.
5. Schuraytz, I. M. et al. Stainless Steel Use in Sludge Incinerator Gas Scrubbers. Public Works. J03(2):55-57,
February 1972.
6. Liao, P. Design Method for Fluidized Bed Sewage Sludge Incinerators. PhD. Thesis. University of Washington,
Seattle, Washington, 1972.
7. Source test data supplied by the Detroit Metropolitan Water Department, Detroit, Michigan. 1973.
8. Source test data from Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency,
Research Triangle Park, N.C. 1972.
9. Source test data from Dorr-Oliver, Inc., Stamford, Connecticut. 1973.
2.5-2 EMISSION FACTORS
5/74
-------
3. INTERNAL COMBUSTION ENGINE SOURCES
The internal combustion engine in both mobile and stationary applications is a major source of air pollutant
emissions. Internal combustion engines were responsible for approximately 73 percent of the carbon monoxide,
56 percent of the hydrocarbons, and 50 percent of the nitrogen oxides (NOX as NOj) emitted during 1970 in the
United States.1 These sources, however, are relatively minor contributors of total particulate and sulfur oxides
emissions. In 1970, nationwide, internal combustion sources accounted for only about 2.5 percent of the total
particulate and 3.4 percent of the sulfur oxides.1
The three major uses for internal combustion engines are: to propel highway vehicles, to propel off-highway
vehicles, and to provide power from a stationary position. Associated with each of these uses are engine duty
cycles that have a profound effect on the resulting air pollutant emissions from the engine. The following sections
describe the many applications of internal combustion engines, the engine duty cycles, and the resulting
emissions.
DEFINITIONS USED IN CHAPTER 3
Calendar year - A cycle in the Gregorian calendar of 365 or 366 days divided into 12 months beginning with
January and ending with December.
Catalytic device - A piece of emission control equipment that is anticipated to be the major component used in
post 1974 light-duty vehicles to meet the Federal emission standards.
Cold vehicle operation — The first 505 seconds of vehicle operation following a 4-hour engine-off period, (for
catalyst vehicles a 1-hour engine-off period).
Composite emission factor (highway vehicle) — The emissions of a vehicle in gram/mi (g/km) that results from the
product of the calendar year emission rate, the speed correction factor, the temperature correction factor, and
the hot/cold weighting correction factor.
Crankcase emissions - Airborne substance emitted to the atmosphere from any portion of the crankcase
ventilation or lubrication systems of a motor vehicle engine.
7975 Federal Test Procecure (FTP) ~ The Federal motor vehicle emission test as described in the Federal
Register, Vol. 36, Number 128, July 2, 1971.
Fuel evaporative emissions - Vaporized fuel emitted into the atmosphere from the fuel system of a motor
vehicle.
Heavy-duty vehicle — A motor vehicle designated primarily for transportation of property and rated at more than
8500 pounds (3856 kilograms) gross vehicle weight (GVW) or designed primarily for transportation of persons
and having a capacity of more than 12 persons.
High-altitude emission factors — Substantial changes in emission factors from gasoline-powered vehicles occur as
altitude increases. These changes are caused by fuel metering enrichment because of decreasing air density. No
relationship between mass emissions and altitude has been developed. Tests have been conducted at near sea
level and at approximately 5000 feet (1524 meters) above sea level, however. Because most major U.S. urban
areas at high altitude are close to 5000 feet (1524 meters), an arbitrary value of 3500 ft (1067 m) and above is
used to define high-altitude cities.
Horsepower-hours — A unit of work.
Hot/cold weighting correction factor — The ratio of pollutant exhaust emissions for a given percentage of cold
operation (w) to pollutant exhaust emissions measured on the 1975 Federal Test Procedure (20 percent cold
operation) at ambient temperature (t).
Light-duty truck - Any motor vehicle designated primarily for transportation of property and rated at 8500
pounds (3856 kilograms) GVW or less. Although light-duty trucks have a load carrying capability that exceeds
that of passenger cars, they are typically used primarily for personal transportation as passenger car
substitutes.
Light-duty vehicle (passenger car) — Any motor vehicle designated primarily for transportation of persons and
having a capacity of 12 persons or less.
3.1.1-1
-------
Modal emission model — A mathematical model that can be used to predict the warmed-up exhaust emissions for
groups of light-duty vehicles over arbitrary driving sequences.
Model year — A motor vehicle manufacturer's annual production period. If a manufacturer has no annual
production period, the term "model year" means a calendar year.
Model year mix — The distribution of vehicles registered by model year expressed as a fraction of the total vehicle
population.
Nitrogen oxides — The sum of the nitric oxide and nitrogen dioxide contaminants in a gas sample expressed as if
the nitric oxide were in the form of nitrogen dioxide. All nitrogen oxides values in this chapter are corrected
for relative humidity.
Speed correction factor — The ratio of the pollutant (p) exhaust emission factor at speed "x" to the pollutant (p)
exhaust emission factor as determined by the 1975 Federal Test Procedure at 19.6 miles per hour (31.6
kilometers per hour).
Temperature correction factor - The ratio of pollutant exhaust emissions measured over the 1975 Federal Test
Procedure at ambient temperature (t) to pollutant exhaust emissions measured ovsr the 1975 Federal Test
Procedure at standard temperature conditions (68 to 86°F).
Reference
1. Cavender, J., D. S. Kircher, and J. R. Hammerle. Nationwide Air Pollutant Trends (1940-1970). U. S.
Environmental Protection Agency, Office of Air and Water Programs. Research Triangle Park, N.C. Publication
Number AP-115. April 1973.
3.1 HIGHWAY VEHICLES
Passenger cars, light trucks, heavy trucks, and motorcycles comprise the four main categories of highway
vehicles. Within each of these categories, powerplant and fuel variations result in significantly different emission
characteristics. For example, heavy trucks may be powered by gasoline or diesel fuel or operate on a gaseous fuel
such as compressed natural gas (CNG).
It is important to note that highway vehicle emission factors change with time and, therefore, must be
calculated for a specific time period, normally one calendar year. The major reason for this time dependence is
the gradual replacement of vehicles without emission control equipment by vehicles with control equipment, as
well as the gradual deterioration of vehicles with control equipment as they accumulate age and mileage. The
emission factors presented in this chapter cover only calendar years 1971 and 1972 and are based on analyses of
actual tests of existing sources and control systems. Projected emission factors for future calendar years are no
longer presented in this chapter because projections are "best guesses" and are best presented independently of
analytical results. The authors are aware of the necessity for forecasting emissions; therefore, projected emission
factors are available in Appendix D of this document.
Highway vehicle emission factors are presented in two forms in this chapter. Section 3.1.1 contains average
emission factors for calendar year 1972 for selected values of vehicle miles traveled by vehicle type (passenger
cars, light trucks, and heavy trucks), ambient temperature, cold/hot weighting, and average vehicle speed. The
section includes one case that represents the average national emission factors as well as thirteen other scenarios
that can be used to assess the sensitivity of the composite emission factor to changing input conditions. All
emission factors are given in grams of pollutant per kilometer traveled (and in grams of pollutant per mile
traveled).
The emission factors given in sections 3.1.2 through 3.1.7 are for individual classes of highway vehicles and
their application is encouraged if specific statistical data are available for the area under study. The statistical data
required include vehicle registrations by model year and vehicle type, annual vehicle travel in miles or kilometers
by vehicle type and age, average ambient temperature, percentage of cold-engine operation by vehicle type, and
average vehicle speed. When regional inputs are not available, national values (which are discussed) may be
applied.
3.1.1-2 EMISSION FACTORS 12/75
-------
3.1.1 Average Emission Factors for Highway Vehicles revised by David S. Kircher
and Marcia E. Williams
3.1.1.1 General-Emission factors presented in this section are intended to assist those individuals interested in
compiling approximate mobile source emission estimates for large areas, such as an individual air quality region or
the entire nation, for calendar year 1972. Projected mobile source emission factors for future years are no longer
presented in this section. This change in presentation was made to assure consistency with the remainder of this
publication, which contains emission factors based on actual test results on currently controlled sources and
pollutants. Projected average emission factors for vehicles are available, however, in Appendix D of this
publication.
The emission factor calculation techniques presented in sections 3.1.2 through 3.1.5 of this chapter are
strongly recommended for the formulation of localized emission estimates required for air quality modeling or
for the evaluation of air pollutant control strategies. Many factors, which vary with geographic location and
estimation situation, can affect emission estimates considerably. The factors of concern include average vehicle
speed, percentage of cold vehicle operation, percentage of travel by vehicle category (automobiles, light trucks,
heavy trucks), and ambient temperature. Clearly, the infinite variations in these factors make it impossible to
present composite mobile source emission factors for each application. An effort has been made, therefore, to
present average emission factors for a range of conditions. The following conditions are considered for each of
these cases:
Average vehicle speed — Two vehicle speeds are considered. The first is an average speed of 19.6 mi/hr (31.6
km/hr), which should be typical of a large percentage of urban vehicle operation. The second is an average speed
of 45 mi/hr (72 km/hr), which should be typical of highway or rural operation.
Percentage of cold operation - Three percentages of cold operation are considered. The first (at 31.6 km/hr)
assumes that 20 percent of the automobiles and light trucks are operating in a cold condition (representative of
vehicle start-up after a long engine-off period) and that 80 percent of the automobiles and light trucks are
operating in a hot condition (warmed-up vehicle operation). This condition can be expected to assess the engine
temperature situation over a large area for an entire day. The second situation assumes that 100 percent of the
automobiles and light trucks are operating in a hot condition (at 72 km/hr). This might be applicable to rural or
highway operation. The third situation (at 31.6 km/hr) assumes that 100 percent of the automobiles and light
trucks are operating in a cold condition. This might be a worst-case situation around an indirect source such as a
sports stadium after an event lets out. In all three situations, heavy-duty vehicles are assumed to be operating in a
hot condition.
Percentage of travel by vehicle type - Three situations are considered. The first (at both 31.6 km/hr and 72
km/hr) involves a nationwide mix of vehicle miles traveled by automobiles, light trucks, heavy gasoline trucks,
and heavy diesel trucks. The specific numbers are 80.4, 11.8, 4.6, and 3.2 percent of total vehicle miles traveled,
respectively.1 • 2 The second (at 31.6 km/hr) examines a mix of vehicle miles traveled that might be found in a
central city area. The specific numbers are 63, 32, 2.5, and 2.5 percent, respectively. The third (31.6 km/hr)
examines a mix of vehicles that might be found in a suburban location or near a localized indirect source where
no heavy truck operation exist. The specific numbers are 88.2, 11.8, 0, and 0 percent, respectively.
Ambient temperature — Two situations at 31.6 km/hr are considered: an average ambient temperature of 24°C
(75°F) and an average ambient temperature of 10°C (50°F).
Table 3.1.1-1 presents composite CO, HC, and NOX factors for the 13 cases discussed above for calendar year
1972. Because particulate emissions and sulfur oxides emissions are not assumed to be functions of the factors
discussed above, these emission factors are the same for all scenarios and are also presented in the table. The table
entries were calculated using the techniques described and data presented in sections 3.1.2, 3.1.4, and 3.1.5 of
this chapter. Examination of Table 3.1.1-1 can indicate the sensitivity of the composite emission factor to various
12/75 Internal Combustion Engine Sources 3.1.1-3
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EMISSION FACTORS
12/75
-------
conditions. A user who has specific data on the input factors should calculate a composite factor to fit the exact
scenario. When specific input factor data are not available, however, it is hoped that the range of values presented
in the table will cover the majority of applications. The user should be sure, however, that the appropriate
scenario is chosen to fit the situation under analysis. In many cases, it is not necessary to apply the various
temperature, vehicle speed, and cold/hot operation correction factors because the basic emission factors (24°C,
31.6 km/hr, 20 percent cold operation, nationwide mix of travel by vehicle category) are reasonably accurate
predictors of motor vehicle emissions on a regionwide (urban) basis.
References for Section 3.1.1
1. Highway Statistics 1971. U.S. Department of Transportation. Federal Highway Administration. Washington,
D.C. 1972. p. 81.
2. 1972 Census of Transportation. Truck Inventory and Use Survey. U.S. Department of Commerce. Bureau of
the Census. Washington, D.C. 1974.
12/75 Internal Combustion Engine Sources 3.1.1-5
-------
-------
3.1.2 Light-Duty, Gasoline-Powered Vehicles (Automobiles) by David S. Kircher,
Marcia E. Williams,
and Charles C. Masser
3.1.2.1 General - Because of their widespread use, light-duty vehicles (automobiles) are responsible for a large
share of air pollutant emissions in many areas of the United States. Substantial effort has been expended recently
to accurately characterize emissions from these vehicles.1'2 The methods used to determined composite
automobile emission factors have been the subject of continuing EPA research, and, as a result, two different
techniques for estimating CO, HC, and NOX exhaust emission factors are discussed in this section.
The first method, based on the Federal Test Procedure (FTP),3'4 is a modification of the procedure that was
discussed in this chapter in earlier editions of AP-42. The second and newer procedure, "modal" emissions
analysis, enables the user to input a specific driving pattern (or driving "cycle") and to arrive at an emissions
rate.5 The modal technique driving "modes", which include idle, steady-speed cruise, acceleration, and
deceleration, are of sufficient complexity that computerization was required. Because of space limitations, the
computer program and documentation are not provided in this section but are available elsewhere.5
In addition to the methodologies presented for calculating CO, HC, and NOX exhaust emissions, data are given
later in this section for emissions in the idle mode, for crankcase and evaporative hydrocarbon emissions, and for
particulate and sulfur oxides emissions.
3.1.2.2 FTP Method for Estimating Carbon Monoxide, Exhaust Hydrocarbons and Nitrogen Oxides Emission
Factors — This discussion is begun with a note of caution. At the outset, many former users of this method may
be somewhat surprised by the organizational and methodological changes that have occurred. Cause for concern
may stem from: (1) the apparent disappearance of "deterioration" factors and (2) the apparent loss of the
much-needed capability to project future emission levels. There are, however, substantive reasons for the changes
implemented herein.
Results from EPA's annual surveillance programs (Fiscal Years 1971 and 1972) are not yet sufficient to yield a
statistically meaningful relationship between emissions and accumulated mileage. Contrary to the previous
assumption, emission deterioration can be convincingly related not only to vehicle mileage but also to vehicle age.
This relationship may not come as a surprise to many people, but the complications are significant. Attempts to
determine a functional relationship between only emissions and accumulated mileage have indicated that the data
can fit a linear form as well as a non-linear (log) form. Rather than attempting to force the data into a
mathematical mold, the authors have chosen to present emission factors by both model year and calendar year.
The deterioration factors are, therefore, "built in" to the emission factors. This change simplifies the calculations
and represents a realistic, sound use of emission surveillance data.
The second change is organizational: emission factors projected to future years are no longer presented in this
section. This is in keeping with other sections of the publication, which contains emission factors only for
existing sources based on analyses of test results. As mentioned earlier, projections are "best guesses" and are best
presented independently of analytical results (see Appendix D).
The calculation of composite exhaust emission factors using the FTP method is given by:
*
n
e
npstw / _, Hpn min vips npt Mptw (3.1.2-1)
4 i=n-12
where: enpStw = Composite emission factor in g/mi (g/km) for calendar year (n), pollutant (p), average
speed (s), ambient temperature (t), and percentage cold operation (w)
12/75 Internal Combustion Engine Sources 3.1.2-1
-------
C'
min
vips
zipt
riptw
The FTP (1975 Federal Test Procedure) mean emission factor for the i model year
light-duty vehicles during calendar year (n) and for pollutant (p)
The fraction of annual travel by the i ] model year light-duty vehicles during calendar year
(n)
The speed correction factor for the i 1 model year light-duty vehicles for pollutant (p) and
average speed (s)
The temperature correction factor for the i model year light-duty vehicles for pollutant
(p) and ambient temperature (t)
The hot/cold vehicle operation correction factor for the i model year light-duty vehicles
for pollutant (p), ambient temperature (t), and percentage cold operation (w)
The data necessary to complete this calculation for any geographic area are presented in Tables 3.1.2-1
through 3.1.2-8. Each of the variables in equation 3.1.2-1 is described in greater detail below, after which the
technique is illustrated by an example.
Table 3.1.2-1. CARBON MONOXIDE, HYDROCARBON, AND NITROGEN OXIDES
EXHAUST EMISSION FACTORS FOR LIGHT-DUTY VEHICLES
-EXCLUDING CALIFORNIA-FOR CALENDAR YEAR 1971a-b
(BASED ON 1975 FEDERAL TEST PROCEDURE)
EMISSION FACTOR RATING: A
Location
and
model year
Low altitude
Pre-1968
1968
1969
1970
1971
High altitude
Pre-1968
1968
1969
1970
1971
Carbon
monoxide
g/mi
86.5
67.8
61.7
47.6
39.6
126.9
109.2
76.4
94.8
88.0
g/km
53.7
42.1
38.3
29.6
24.6
78.8
67.8
47.4
58.9
54.6
Hydrocarbons
g/mi
8.74
5.54
5.19
3.77
3.07
10.16
7.34
6.31
6.71
5.6
g/km
5.43
3.44
3.22
2.34
1.91
6.31
4.59
3.91
4.17
3.48
Nitrogen
oxides
g/mi
3.54
4.34
5.45
5.15
5.06
1.87
2.20
2.59
2.78
3.05
g/km
2.20
2.70
3.38
3.20
3.14
1.17
1.37
1.61
1.73
1.89
a!Mote: The values in this table can be used to estimate emissions only for calendar year 1971 This reflects a substantial change
over pa , presentation of data in this chapter (see text for details).
References 1 and 2. These references summarize and analyze the results of emission tests of light-duty vehicles in several U S.
cities.
3.1.2-2
EMISSION FACTORS
12/75
-------
Table 3.1.2-2. CARBON MONOXIDE, HYDROCARBON, AND NITROGEN OXIDES EXHAUST
EMISSION FACTORS FOR LIGHT-DUTY VEHICLES-STATE OF CALIFORNIA ONLY-FOR
CALENDAR YEAR 1971a-b
(BASED ON 1975 FEDERAL TEST PROCEDURE)
EMISSION FACTOR RATING: A
Location
and
model year
California
Pre-1966c
1966
1967
1968C
1969C
1970C
1971
Carbon
monoxide
g/mi
86.5
65.2
67.2
67.8
61.7
50.8
42.3
g/km
53.7
40.5
41.7
42.1
38.3
31.5
26.3
Hydrocarbons
g/mi
8.74
7.84
5.33
5.54
5.19
4.45
3.02
g/km
5.43
4.87
3.31
3.44
3.22
2.76
1.88
Nitrogen
oxides
g/mi
3.54
3.40
3.42
4.34
5.45
4.62
3.83
g/km
2.20
2.11
2.12
2.70
3.38
2.87
2.38
aNote: The values in this table can be used to estimate emissions only for calendar year 1971. This reflects a substantial change
past presentations of data in this chapter (see text for details)
^References 1. This reference summarizes and analyzes the results of emission tests of light-duty vehicles in Los Angeles as well
as five other U.S. cities during 1971-1972.
cData for these model years are mean emission test values for the five low altitude test cities summarized in Reference 1.
Table 3.1.2.-3. CARBON MONOXIDE, HYDROCARBON, AND NITROGEN OXIDES EXHAUST
EMISSION FACTORS FOR LIGHT-DUTY VEHICLES-EXCLUDING CALIFORNIA-FOR
CALENDAR YEAR 1972a'b
(BASED ON 1975 FEDERAL TEST PROCEDURE)
EMISSION FACTOR RATING: A
Location
and
model year
Low altitude
Pre-1968
1968
1969
1970
1971
1972
High altitude
Pre-1968
1968
1969
1970
1971
1972
Carbon
monoxide
g/mi
93.5
63.7
64.2
53.2
51.1
36.9
141.0
101.4
97.8
87.5
80.3
80.4
9/krn
58.1
39.6
39.9
33.0
31.7
22.9
87.6
63.0
60.7
54.3
49.9
50.0
Hydrocarbons
g/mi
8.67
6.33
4.95
4.89
3.94
3.02
11.9
6.89
5.97
5.56
5.19
4.75
g/km
5.38
3.93
3.07
3.04
2.45
1.88
7.39
4.26
3.71
3.45
3.22
2.94
Nitrogen
oxides
g/mi
3.34
4.44
5.00
4.35
4.30
4.55
2.03
2.86
2.93
3.32
2.74
3.08
g/km
2.07
2.76
3.10
2.70
2.67
2.83
1.26
1.78
1.82
2.06
1.70
1.91
al\lote' The values in this table can be used to estimate emissions only for calendar year 1972 This reflects a substantial change
over past presentation of data in this chapter (see text for details).
Reference 2. This reference summarizes and analyzes the results of emission tests of light-duty vehicles in six U.S. metropolitan
areas during 1972-1973.
12/75
Internal Combustion Engine Sources
3.1.2-3
-------
Table 3.1.2-4. CARBON MONOXIDE, HYDROCARBON, AND NITROGEN OXIDES EXHAUST
EMISSION FACTORS FOR LIGHT-DUTY VEHICLES-STATE OF CALIFORNIA ONLY-FOR
CALENDAR YEAR 1972a-b
(BASED ON 1975 FEDERAL TEST PROCEDURE)
EMISSION FACTOR RATING: A
Location
and
model year
California
Pre-1 966°
1966
1967
1968C
1969C
1970
1971
1972
Carbon
monoxide
g/mi
93.5
86.9
75.4
63.7
64.2
78.5
59.7
46.7
g/km
58.1
54.0
46.8
39.6
39.9
48.7
37.1
29.0
Hydrocarbons
g/mi
8.67
7.46
5.36
6.33
4.95
6.64
3.98
3.56
g/km
5.38
4.63
3.33
3.93
3.07
4.12
2.47
2.21
Nitrogen
oxides
g/mi
3.34
3.43
3.77
4.44
5.00
4.46
3.83
3.81
g/km
2.07
2.13
2.34
2.76
3.10
2.77
2.38
2.37
al\lote: The values in this table can be used to estimate emissions only for calendar year 1972. This represents a substantial change
over past presentation of data in this chapter (see text for details).
"Reference 2. This reference summarizes and analyzes the results of emission tests of light-duty vehicles m Los Angeles as well as
in five other U.S. cities during 1972-1973.
cData for these model years are mean emission test values for the five low altitude test cities summarised in Reference 2.
Table 3.1.2-5. SAMPLE CALCULATION OF FRACTION OF LIGHT-DUTY
VEHICLE ANNUAL TRAVEL BY MODEL YEAR3
Age,
years
1
2
3
4
5
6
7
8
9
10
11
12
>13
1972
Fraction of total
vehicles in use
nationwide (a)b
0.083
0.103
0.102
0.106
0.099
0.087
0.092
0.088
0.068
0.055
0.039
0.021
0.057
Average annual
miles driven (b)c
15,900
15,000
14,000
13,100
12,200
11,300
10,300
9,400
8,500
7,600
6,700
6,700
6,700
a x b
1,320
1,545
1,428
1,389
1,208
983
948
827
578
418
261
141
382
1972
Fraction
of annual
travel (m)d
0.116
0.135
0.125
0.122
0.106
0.086
0.083
0.072
0.051
0.037
0.023
0.012
0.033
References 6 and 7.
bThese data are for July 1, 1972, from Reference 7 and represent the U.S. population of light-duty vehicles by model year for that
year only.
cMileage values are the results of at least squares analysis of data in Reference 6.
dm=ab/Sab.
3.1.2-4
EMISSION FACTORS
12/75
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hould not be ext
ee Table 3.1.2-7
tor equations anc
af units, it is sugg
calculations can
aReference 8 Equations s
mi/hr; 8 and 16 km/hrl s
The speed correction fac
using the metric system
are determined, all other
12/75
Internal Combustion Engine Sources
3.1.2-5
-------
Table 3.1.2-7. LOW AVERAGE SPEED CORRECTION
FACTORS FOR LIGHT-DUTY VEHICLES3
Location
Low altitude
(Excluding 1966-
1967 Calif.)
California
Low altitude
High altitude
Model
year
1957-1967
1966-1967
1968
1969
1970
1971-1972
1957-1967
1968
1969
1970
1971-1972
Carbon monoxide
5 mi/hr
|8 km/hr)
2.72
1.79
3.06
3.57
3.60
4.15
2.29
2.43
2.47
2.84
3.00
10 mi/hr
(16 km/hr)
1.57
1.00
1.75
1.86
1.88
2.23
1.48
1.54
1.61
1.72
1.83
Hydrocarbons
5 mi/hr 10rni/hr
(8 km/hr) j (16 km/hr)
2.50
1.87
2.96
2.95
2.51
2.75
2.34
2.10
2.04
2.35
1.45
1.12
1.66
1.65
1.51
1.63
1.37
1.27
1.22
1.36
2.17 ! 1.35
Nitrogen oxides
5 mi/hr
(8 km/hr)
1.08
1.16
1.04
1.08
1.13
1.15
1.33
1.22
1.22
1.19
10 mi/hr
(16 km/hr)
1.03
1.09
1.00
1.05
1.05
1.03
1.20
1.18
1.08
1.11
1 .06 ; 1 .02
aDriving patterns developed from CAPE-21 vehicle operation data (Reference 9) were input to the modal emission analysis model
(see section 3.1.2.3). The results predicted by the model (emissions at 5 and 10 mi/hr; 8 and 16 krn/hr) were divided by FTP
emission factors for hot operation to obtain the above results. The above data are approximate and represent the best currently
available information.
Table 3.1.2-8. LIGHT-DUTY VEHICLE TEMPERATURE CORRECTION FACTORS
AND HOT/COLD VEHICLE OPERATION CORRECTION FACTORS
FOR FTP EMISSION FACTORS8
Pollutant
Carbon monoxide
Hydrocarbons
Nitrogen oxides
Temperature correction
b
-0.01 27 t+ 1.95
-0.01 13 t+ 1.81
-0.0046 t + 1 .36
Hot/Cold operation
correction [f(t)J ^
0.0045 t + 0.02
0.0079 t + 0.03
-0.0068t+ 1.64
aReference 10. Temperature (t) is expressed in F. In order to apply these equations, C must be first converted to F. The ap-
propriate conversion formula is: F=(9/5)C + 32. For temperatures expressed on the Kelvin (K) scale: F=9/5(K-273.16) + 32
''The formulae for z. enable the correction of the FTP emission factors for ambient temperature effects only. The amount of
cold/hot operation is not affected. The formulae for f (t), on the other hand, are part of equation 3.1.2-2 for calculating
The variable r-|ptw corrects for cold/hot operation as well as ambient temperature.
Note: 2 can be applied without r|ptw, but not vica versa.
3.1.2-6
EMISSION FACTORS
12/75
-------
FTP emission factor (cipn). The results of the first two EPA annual light-duty vehicle surveillance programs are
summarized in Tables 3.1.2-1 through 3.1.24. These data for calendar years 1971 and 1972 are divided by
geographic area into: low altitude (excluding California), high altitude (excluding California), and California only.
California emission factors are presented separately because, for several model years, California vehicles have been
subject to emission standards that differ from standards applicable to vehicles under the Federal emission control
program. For those model year vehicles for which California did_ not have separate emission standards, the
national emission factors are assumed to apply in California as well. Emissions at high altitude are differentiated
from those at low altitude to account for the effect that altitude has on air-fuel ratios and concomitant emissions.
Tue tabulated values are applicable to calendar years 1971 and 1972 for each model yeai.
Fraction of annual travel by model year (nij). A sample calculation of this variable is presented in Table 3.1 .2-5.
In the example, nationwide statistics are used, and the fraction of in-use vehicles by model year (vehicle age) is
weighted on the basis of the annual miles driven. The calculation may be "localized" to reflect local (county,
state, etc.) vehicle age mix, annual miles driven, or both. Otherwise, the national data can be used. The data
presented in Table 3.1 .2-5 are for calendar year 1972 only; for later calendar years, see Appendix D.
Speed Correction Factors (vjns). Speed correction factors enable the "adjustment" of FTP emission factors to
account for differences in average route speed. Because the implicit average route speed of the FTP is 19.6 mi/hr
(31 .6 km/hr), estimates of emissions at higher or lower average speeds require a correction.
It is important to note the difference between "average route speed" and "steady speed". Average route speed
is trip-related and based on a composite of the driving modes (idle, cruise, acceleration, deceleration)
encountered, for example, during a typical home-to-work trip. Steady speed is highway facility-oriented. For
instance, a group of vehicles traveling over an uncongested freeway link (with a volume to capacity ratio of 0.1,
for example) might be traveling at a steady speed of about 55 mi/hr (89 km/hr). Note, however, that steady
speeds, even at the link level, are unlikely to occur where resistance to traffic flow occurs (unsynchronized traffic
signaling, congested flow, etc.)
In previous revisions to this section, the limited data available for correcting for average speed were presented
graphically. Recent research, however, has resulted in revised speed relationships by model year/' To facilitate the
presentation, the data are given as equations and appropriate coefficients in Table 3.1.2-6. These relationships
were developed by performing five major tasks. First, urban driving pattern data collected during the CAPE- 10
Vehicle Operations Survey1 ' were processed by city and time of day into freeway, non-freeway, and composite
speed-mode matrices. Second, a large number of driving patterns were computer-generated for a range of average
speeds (15 to 45 mi/hr; 24 to 72 km/mi) using weighted combinations of freeway and non-freeway matrices.
Each of these patterns was filtered for "representativeness." Third, the 88 resulting patterns were input
(second-by-second speeds) to the EPA modal emission analysis model (see sections 3.1.2.3). The output of the
model was estimated emissions for each pattern of 11 vehicle groups (see Table 3.1.2.6 for a listing of these
groups). Fourth, a regression analysis was performed to relate estimated emissions to average route speed for each
of the 1 1 vehicle groups. Fifth, these relationships were normalized to 19.6 mi/hr (31 .6 km/hr) and summarized
in Table 3. 1.2-6.
The equations in Table 3.1 .2-6 apply only for the range of the data — from 15 to 45 mi/hr (24 to 72 km/hr).
Because there is a need, in some situations, to estimate emissions at very low average speeds, correction factors
for 5 and 10 mi/hr (8 and 16 km/hr) presented in Table 3.1.2-7 were developed using a method somewhat like
that described above, again using the modal emission model. The modal emission model predicts emissions from
warmed-up vehicles. The use of this model to develop speed correction factors makes the assumption that a given
speed correction factor applies equally well to hot and cold vehicle operation. Estimation of warmed-up idle
emissions are presented in section 3.1.2.4 on a gram per minute basis.
Temperature Correction Factor (Zjpt). The 1975 FTP requires that emissions measurements be made within the
limits of a relatively narrow temperature band (68 to 86° F). Such a band facilitates uniform testing in
laboratories without requiring extreme ranges of temperature control. Present emission factors for mofor vehicles
are based on data from the standard Federal test (assumed to be at 75°F). Recently, EPA and the Bureau of
Mines undertook a test program to evaluate the effect of ambient temperature on motor vehicle exhaust emission
levels.1 ° The study indicates that changes in ambient temperature result in significant changes in emissions during
cold start-up operation. Because many Air Quality Control Regions have temperature characteristics differing
12/75 Internal Combustion Engine Sources 3.1.2-7
-------
considerably from the 68 to 86°F range, the temperature correction factor should be applied. These correction
factors, which can be applied between 20 and 80°F, are presented in Table 3.1.2-8. For temperatures outside this
range, the appropriate endpoint correction factor should be applied.
Hot/Cold Vehicle Operation Correction Factor (rjptw)- The 1975 FTP measures emissions during: a cold
transient phase (representative of vehicle start-up after a long engine-off period), a hot transient phase
(representative of vehicle start-up after a short engine-off period), and a stabilized phase (representative of
wnriiied-up vehicle operation). The weighting factors used in the 1975 FTP are 20 percent, 27 percent, and 53
percent of total miles (time) in each of the three phases, respectively. Thus, when the 1975 FTP emission factors
are applied to a given region for the purpose of accessing air quality, 20 percent of the light-duty vehicles in the
area of interest are assumed to be operating in a cold condition, 27 percent in a hot start-up condition, and 53
percent in a hot stabilized condition. For non-catalyst equipped vehicles (all pre-1975 model year vehicles),
emissions in the two hot phases are essentially equivalent on a grams per mile (grams per kilometer basis).
Therefore, the 1975 FTP emission factor represents 20 percent cold operation and 80 peicent hot operation.
Many situations exist in which the application of these particular weighting factors may be inappropriate. For
example, light-duty vehicle operation in the center city may have a much higher percentage of cold operation
during the afternoon peak when work-to-home trips are at a maximum and vehicles have been standing for 8
hours. The hot/cold vehicle operation correction factor allows the cold operation phase to range from 0 to 100
percent of total light-duty vehicle operations. This correction factor is a function of the percentage of cold
operation (w) and the ambient temperature (t). The correction factor is:
w + (100-w) f(t)
Vw = 20 + 80f(t) (3-L2"2)
where: f(t) is given in Table 3.1.2-8.
Sample Calculation. As a means of further describing the application of equation 3.1 ..2-1, calculation of the
carbon monoxide composite emission factor is provided as an example. To perform this calculation (or any
calculation using this procedure), the following questions must be answered:
1. What calendar year is being considered?
2. What is the average vehicle speed in the area of concern?
3. Is the area at low altitude (non-California), in California, or at high altitude?
4. Are localized vehicle mix and/or annual travel data available?
5. Which pollutant is to be estimated? (For non-exhaust hydrocarbons see section 3.1.2.5).
6. What is the ambient temperature (if it does not fall within the 68 to 86°F Federal Test Procedure range)?
7. What percentage of vehicle operation is cold operation (first 500 seconds of operation after an engine-off
period of at least 4 hours)?
For this example, the composite carbon monoxide emission factor for 1972 will be estimated for a hypothetical
county. Average vehicle speed for the county is assumed to be 30 mi/hr. The county is at low altitude
(non-California), and localized vehicle mix/annual travel data are unavailable (nationwide statistics are to be
used). The ambient temperature is assumed to be 50°F and the percentage of cold vehicle operation is assumed to
be 40 percent. To simplify the presentation, the appropriate variables are entered in the following tabulation.
3.1.2-8 EMISSION FACTORS * 12/75
-------
Model
year(s)
0.396
0.106
0.122
0.125
0.135
0.116
Variables, a
vips
0.72
0.69
0.63
0.62
0.63
0.63
zipt
1.315
1.315
1.315
1.315
1.315
1.315
riptw
1.39
1.39
1.39
1.39
1.39
1.39
(cjpn)(mjn)(vjps)
30.3
5.3
5.6
4.7
4.9
3.1
enpstw = 53.9 g/km
aThe variable C|Dn above is from Table 3.1.2-3, and the variable m|r) was taken from the sample calculation based on nationwide
data, Table 3.1.2-5. The fraction of travel for pre-1968 (6 years old and older) vehicles is the sum of the last eight values in the
far right-hand column of the table. The speed correction factor (v ) was calculated from the appropriate equations in Table
3.1.2-6. The variable z- t was calculated from the appropriate equation in Table 3.1.2-8. The variable rjptw was calculated using
an equation from Table 3 1.2-8 and equation 3.1.2-2.
The resultant composite carbon monoxide emission factor for 1972 for the hypothetical county is 53.9 g/km
3.1.2.3 Modal Emission Model for Estimating Carbon Monoxide, Hydrocarbons, and Nitrogen Oxides Emission
Factors — The modal emission model and allied computer programs permit an analyst to calculate mass emission
quantities of carbon monoxide, hydrocarbons, and nitrogen oxides emitted by individual vehicles or groups of
vehicles over any specified driving sequence or pattern. The complexity of the model and accompanying
computer programs makes presentation of the entire procedure in this publication impractical. Instead, the
capabilities and limitations of the model are briefly described in the following paragraphs with the details to be
found in a separate report, Automobile Exhaust Emission Modal Analysis Model.s
The modal emission model was developed because of the well-established fact that emission rates for a
particular vehicle depend upon the manner in which it is operated. Stated another way, the emissions from a
particular vehicle are a function of the time it spends in each of four general operating modes (idle, cruise,
deceleration, acceleration) as well as specific operation within each of the four modes. In many situations, use of
the basic FTP emission factors may be sufficient. Certainly, nationwide, statewide, and county-wide emission
estimates that involve spatial aggregation of vehicular travel data lend themselves to the FTP method (section
3.1.2.2). There are, however, a relatively large number of circumstances for which an analyst may require
emission estimates at a zonal or link level of aggregation. The analyst, for example, may be faced with providing
inputs to a carbon monoxide dispersion model, estimating the impact of an indirect source (sports complex,
shopping center, etc.), or preparing a highway impact statement. In such instances, the resources may be available
to determine the necessary inputs to the modal model either by estimation or field studies. These data are input
to the modal model and emission estimates are output.
Although the computer software package is sufficiently flexible to accept any set of input modal emission
data, EPA data based on tests of 1020 individual light-duty vehicles (automobiles) that represent variations in
model year, manufacture, engine and drive train equipment, accumulated mileage, state of maintenance, attached
pollution abatement devices, and geographic location are a part of the package. The user, therefore, need not
input any modal emission data. He inputs the driving sequence desired as speed (mi/hr) versus time (sec) in
1-second intervals and specifies the vehicle mix for which emission estimates are desired (vehicles are grouped by
model year and geographic location). The output of the model can then be combined with the appropriate traffic
volume for the desired time period to yield an emission estimate. The use of the modal emission model to
estimate a composite emission factor does not, however, eliminate the need for temperature and cold/hot
weighting correction factors. The model predicts emissions from warmed-up vehicles at an ambient temperature
of approximately 75°F. The estimate of composite exhaust emission factors using the modal emission model is
given by:
eptw = cp apt bptw (3.1.2-3)
12/75 Internal Combustion Engine Sources 3.1.2-9
-------
where: Cptw = Composite emission factor in grams per mile (g/km) for calendar year 1971, pollutant (p),
ambient temperature (t), percentage cold operation (w), and the specific driving sequence and
vehicle mix specified
Cp = The mean emission factor for pollutant (p) for the specified vehicle mix and driving sequence
3pt = The temperature correction factor for pollutant (p) and temperature (t) for warmed-up
operation
biptw = The hot/cold vehicle operation correction factor for pollutant (p), temperature (t), and
percentage cold operation (w)
The data necessary to compute apt and bplw are given in Table 3.1.2-9. The modal analysis computer program
is necessary to compute C.5
Table 3.1.2-9. LIGHT-DUTY VEHICLE MODAL EMISSION
MODEL CORRECTION FACTORS FOR TEMPERATURE
AND COLD/HOT START WEIGHTING3
Pollutant
Carbon monoxide
Hydrocarbons
Nitrogen oxides
Temperature correction
1.0
1.0
-0.0065 t + 1 .49
Hot/cold temperature
correction [f(t)]
0.0045 t + 0.02
0.0079 t + 0.03
-0.0068 t + 1 .64
aReference 10. Temperature is expressed in F. In order to apply these equations, convert C to F (F=9/5C + 32), or K to F
(F=9/5(K-273.16) + 32).
Temperature Correction Factor (apt). The modal analysis model predicts emissions at approximately 75°F. The
temperature correction factors are expressed in equational form and presented in Table 3.1.2-9.
Hot/Cold Vehicle Operation Correction Factor (bptw)- The modal analysis model predicts emissions during
warmed-up vehicle operation, but there are many urban situations for which this assumption is not appropriate.
The hot/cold vehicle operation correction factor allows for the inclusion of a specific percentage of cold
operation. This correction factor is a function of the percentage of cold operation (w) and the ambient
temperature (t). The correction factor is:
w+(100-w)f(t)
(3.1.2-4)
100 f(t)
where: f(t) is given in Table 3.1.2-9.
It is important that potential users of modal analysis recognize of the important limitations of the model.
Although the model provides the capability of predicting emission estimates for any driving pattern, it can only
predict emissions for the vehicle groups that have been tested. Presently this capability is limited to 1971 and
older light-duty vehicles. Efforts are underway to add additional model years (1972-1974), and new models will
be tested as they become available. Although the model is not directly amenable to projecting future year
emissions, it can predict "base" year emissions. Future year emissions can be estimated using the ratio of future
year to base year emissions based on FTP composite emission factors. Finally, the technique requires the input of
a driving sequence and the use of a computer, and is therefore, more complex and more costly to use than the
simple FTP technique (section 3.1.2.1).
3.1.2-10 EMISSION FACTORS 12/75
-------
The modal procedure discussion in this section is recommended when the user is interested in comparing
emissions over seveial different specific driving scenarios. Such an application will result in more accurate
comparisons than can be obtained by the method given in section 3.1.2.2. For other applications where average
speed is all that is known or when calendar year to calendar year comparisons are required, the method in section
3.1.2.2 is recommended.
3.1.2.4 Carbon Monoxide. Hydrocarbon, and Nitrogen Oxides Idle Emission Factors — Estimates of emissions
during a vehicles' idle operating mode may be appropriate at trip attractions such as shopping centers, airports,
sports complexes, etc. Because idle emission factors are expressed (by necessity) in terms of elapsed time,
emissions at idle can be estimated using vehicle operating minutes rather than the conventional vehicle miles of
travel.
Application of the idle values (Table 3.1.2-10) requires calculation of a composite idle emission factor (cp)
through the use of the variable mjn(see section 3.1.2.2) and i1D (idle pollutant p emission factor for the jth model
year). Tue temperature and hot/cold weighting factors presented in Table 3.1.2-9 apply to idle emissions. The
tabulated values are based on warmed-up emissions. (For a t, see Table 3.1.2-9; for b tw, see Table 3.1.2-9 and
equation 3.1.2A.)
Table 3.1.2-10. CARBON MONOXIDE, HYDROCARBON, AND
NITROGEN OXIDES EMISSION FACTORS FOR LIGHT-DUTY
VEHICLES IN WARMED-UP IDLE MODE5
(grams/minute)
Location and
model year(s)
Low altitude
Pre-1968
1968
1969
1970
1971
High altitude
Pre-1968
1968
1969
1970
1971
California only
(low altitude)
Pre-1966
1966
1967
1968
1969
1970
1971
Carbon monoxide
16.9
15.8
17.1
13.1
13.0
18.6
16.8
16.6
16.6
16.9
16.9
18.7
18.7
15.8
17.1
19.3
13.3
Exhaust hydrocarbons
1.63
1.32
1.17
0.73
0.63
1.83
1.09
0.90
1.13
0.80
1.63
1.27
1.27
1.32
1.17
0.76
0.78
Nitrogen oxides
0.08
0.12
0.12
0.13
0.11
0.11
0.11
0.10
0.11
0.16
0.08
0.07
0.07
0.12
0.12
0.28
0.18
aReference 12.
12/75
Internal Combustion Engine Sources
3.1.2-11
-------
The mathematical expression is simply:
n
Hp min apt bptw
(3.1.2-5)
Because the idle data are from the same data base used to develop the modal analysis procedure, they are
subject to the same limitations. Most importantly, idle values cannot be directly used to estimate fulure
emissions.
3.1 .2.5 Crankcase and Evaporative Hydrocarbon Emission Factors — In addition to exhaust emission factors, the
calculation of hydrocarbon emission from gasoline motor vehicles involves evaporative and crankcase
hydrocarbon emission factors. Composite crankcase emissions can be determined using:
fn=
hi
where. i
m
m
i = n-12
composite crankcase hydrocarbon emission factor for calendar year (n)
The crankcase emission factor for the i"1 model year
The weighted annual travel of the i^1 year during calendar year (n)
Crankcase hydrocarbon emission factor by model year are summarized in Table 3.1 .2-1 1 .
The two major sources of evaporative hydrocarbon emissions from light -duty vehicles are the fuel tank and the
carburetor system. Diurnal changes in ambient temperature result in expansion of the air-fuel mixture in a
partially filled fuel tank. As a result, gasoline vapor is expelled to the atmosphere. Running losses from the fuel
tank occur as the fuel is heated by the road surface during driving, and hot-soak losses from the carburetor system
occur after engine shut down at the end of a trip. These carburetor losses are from locations such as: the
Table 3.1.2-11. CRANKCASE HYDROCARBON
EMISSIONS BY MODEL YEAR
FOR LIGHT-DUTY VEHICLES
EMISSION FACTOR RATING: B
Model year
California only
Pre-1961
1961 through 1963
1964 through 1967
Post- 1967
All areas except
California
Pre-1963
1963 through 1967
Post-1967
Hydrocarbons
g/mi
4.1
0.8
0.0
0.0
4.1
0.8
0.0
g/km
2.5
0.5
0.0
0.0
2.5
0.5
0.0
a Reference 13.
3.1.2-12
EMISSION FACTORS
12/75
-------
carburetor vents, the float bowl, and the gaps around the throttle and choke shafts. Because evaporative emissions
are a function of the diurnal variation in ambient temperature and the number of trips per day, emissions are
best calculated in terms of evaporative emissions per day per vehicle. Emissions per day can be converted to
emissions per mile (if necessary) by dividing by an average daily miles per vehicle value. This value is likely to vary
from location to location, however. The composite evaporative hydrocarbon emission factor is given by:
i=n-12
(§i + kid) (nij)
(3.1.2-7)
where: e
n
111;
= The composite evaporative hydrocarbon emission factor for calendar year (n) in Ib/day
(g/day)
= The diurnal evaporative hydrocarbon emission factor for model year (i) in Ib/day (g/day)
= The hot soak evaporative emission factor in Ib/trip (g/trip) for the i™1 model year
= The number of daily trips per vehicle (3.3 trips/vehicle-day is the nationwide average)
= The fraction of annual travel by the i model year during calendar year n
The variables g[ and kj are presented in Table 3.1.2-12 by model year.
Table 3.1.2-12. EVAPORATIVE HYDROCARBON EMISSION FACTORS BY MODEL YEAR
FOR LIGHT-DUTY VEHICLES3
EMISSION FACTOR RATING: A
Location and
model year
Low altitude
Pre-1970
1970 (Calif.)
1970 (non-Calif.)
1971
1972
High altituded
Pre-1971
1971-1972
By sourceb
Diurnal, g/day
26.0
16.3
26.0
16.3
12.1
37.4
17.4
Hot soak, g/trip
14.7
10.9
14.7
10.9
12.0
17.4
14.2
Composite emissions0
g/day
74.5
52.3
74.5
52.3
51.7
94.8
64.3
g/mi
2.53
1.78
2.53
1.78
1.76
3.22
2.19
g/km
1.57
1.11
1.57
1.11
1.09
2.00
1.36
References 1, 14 and 15.
"See text for explanation.
cGram per day values are diurnal emissions plus hot soak emisssions multiplied by the average number of trips per day. Nationwide
data from References 16 and 17 indicate that the average vehicle is used for 3.3 trips per day. Gram per mile values were deter-
mined by dividing average g/day by the average nationwide travel per vehicle (29.4 mi/day) from Reference 16.
^Vehicles without evaporative control were not tested at high altitude. Values presented here are the product of the ratio of pre-
1971 (low altitude) evaporative emissions to 1972 evaporative emissions and 1971-1972 high altitude emissions.
3.1.2.6 Particulate and Sulfur Oxide Emissions - Light-duty, gasoline-powered vehicles emit relatively small
quantities of particulate and sulfur oxides in comparison with the emissions of the three pollutants discussed
above. For this reason, average rather than composite emission factors should be sufficiently accurate for
approximating particulate and sulfur oxide emissions from light-duty, gasoline-powered vehicles. Average
emission factors for these pollutants are presented in Table 3.1.2-13. No Federal standards for these two
pollutants are presently in effect, although many areas do have opacity (antismoke) regulations applicable to
motor vehicles.
12/75
Internal Combustion Engine Sources
3.1.2-13
-------
Table 3.1.2-13. PARTICULATE AND SULFUR OXIDES
EMISSION FACTORS FOR LIGHT-DUTY VEHICLES
EMISSION FACTOR RATING: C
Pollutant
Paniculate3
Exhaust
Tire wear
Sulfur oxides
(SOxasS02)
Emissions for Pre-1973 vehicles
g/mi
0.34
0.20
0.13
a/km
0.21
0.12
0.08
References 18, 19, and 20.
''Based on an average fuel consumption of 13.6 mi/gal (5.8 km/liter) from
Reference 21 and on the use of a fuel with a 0.032 percent sulfur content
from References 22 through 24 and a density of 6.1 Ib/gal (0.73 kg/liter)
from References 22 and 23.
References for Section 3.1.2
1. Automobile Exhaust Emission Surveillance. Calspan Corporation, Buffalo, N.Y. Prepared for Environmental
Protection Agency, Ann Arbor, Mich. Under Contract No. 68-01-0435. Publication No. APTD-1544. March
1973.
2. Williams, M. E., J. T. White, L. A. Platte, and C. J. Domke. Automobile Exhaust Emission Surveillance -
Analysis of the FY 72 Program. Environmental Protection Agency, Ann Arbor, Mich. Publication No.
EPA-460/2-74-001. February 1974.
3. Title 40-Protection of Environment. Control of Air Pollution from New Motor Vehicles and New Motor
Vehicle Engines. Federal Register. Part II. 35(219): 17288-17313, November 10,1970.
4. Title 40-Protection of Environment. Exhaust Emission Standards and Test Procedures. Federal Register. Part
11.56(128): 12652-12664, July 2, 1971.
5. Kunselman, P., H. T. McAdams, C. J. Domke, and M. Williams. Automobile Exhaust Emission Modal
Analysis Model. Calspan Corporation, Buffalo, N. Y. Prepared for Environmental Protection Agency, Ann
Arbor, Mich. Under Contract No. 68-01-0435. Publication No. EPA-460/3-74-005. January 1974.
6. Strate, H. E. Nationwide Personal Transportation Study - Annual Miles of Automobile Travel. Report
Number 2. U.S. Department of Transportation, Federal Highway Administration, Washington, D.C. April
1972.
7. 1973/74 Automobile Facts and Figures. Motor Vehicle Manufacturers Association, Detroit, Mich. 1974.
8. Smith, M. Development of Representative Driving Patterns at Various Average Route Speeds. Scott Research
Laboratories, Inc., San Bernardino, Calif. Prepared for Environmental Protection Agency, Research Triangle
Park, N.C. February 1974. (Unpublished report.)
9. Heavy-duty vehicle operation data. Collected by Wilbur Smith and Associates, Columbia, S.C. under contract
to Environmental Protection Agency, Ann Arbor, Mich. December 1974.
10. Ashby, H. A., R. C. Stahman, B. H. Eccleston, and R. W. Hum. Vehicle Emissions - Summer to Winter.
(Presented at Society of Automotive Engineers meeting. Warrendale, Pa. October 1974. Paper No. 741053.)
3.1.2-14 EMISSION FACTORS 12/75
-------
11. Vehicle Operations Survey. Scott Research Laboratories, Inc., San Bernardino, Calif. Prepared under contract
for Environmental Protection Agency, Ann Arbor, Mich, and Coordinating Research Council, New York,
N.Y. December 1971. (unpublished report.)
12. A Study of Emissions From Light Duty Vehicles in Six Cities. Automotive Environmental Systems, Inc.,
Westminister, Calif. Prepared for Environmental Protection Agency, Ann Arbor, Mich. Under Contract No.
68-04-0042. Publication No. APTD-1497. March 1973.
13. Sigworth, H. W., Jr. Estimates of Motor Vehicle Emission Rates. Environmental Protection Agency, Research
Triangle Park, N.C. March 1971. (Unpublished report.)
14. Liljedahl, D. R. A Study of Emissions from Light Duty Vehicles in Denver, Houston, and Chicago. Fiscal
Year 1972. Automobile Testing Laboratories, Inc., Aurora, Colo. Prepared for Environmental Protection
Agency, Ann Arbor, Mich. Publication No. APTD-1504. July 1973.
15. A Study of Emissions from 1966-1972 Light Duty Vehicles in Los Angeles and St. Louis. Automotive
Environmental Systems, Inc., Westminister, Calif. Prepared for Environmental Protection Agency, Ann
Arbor, Mich. Under Contract No. 68-01-0455. Publication No. APTD-1505. August 1973.
16. Goley, B. T., G. Brown, and E. Samson. Nationwide Personal Transportation Study. Household Travel in the
United States. Report No.7., U.S. Department of Transportation. Washington, D.C. December 1972.
17. 1971 Automobile Facts and Figures. Automobile Manufacturers Association. Detroit, Mich. 1972.
18. Control Techniques for Particulate Air Pollutants. U.S. Department of Health, Education and Welfare,
National Air Pollution Control Administration, Washington, D.C. Publication Number AP-51. January 1969.
19. Ter Haar, G. L., D. L. Lenare, J. N. Hu, and M. Brandt. Composition Size and Control of Automotive
Exhaust Particulates. J. Air Pol. Control Assoc. 22:39-46, January 1972.
20. Subramani, J. P. Particulate Air Pollution from Automobile Tire Tread Wear. Ph. D. Dissertation. University
of Cincinnati, Cincinnati, Ohio. May 1971.
21. 1970 Automobile Facts and Figures. Automobile Manufacturers Association. Detroit, Mich. 1972.
22. Shelton, E. M. and C. M. McKinney. Motor Gasolines, Winter 1970-1971. U.S. Department of the Interior,
Bureau of Mines, Bartlesville, Okla. June 1971.
23. Shelton, E. M. Motor Gasolines, Summer 1971. U.S. Department of the Interior, Bureau of Mines,
Bartlesville, Okla. January 1972.
24. Automotive Fuels and Air Pollution. U.S. Department of Commerce, Washington, D.C. March 1971.
12/75 Internal Combustion Engine Sources 3.1.2-15
-------
-------
3.1.3 Light-Duty, Diesel-Powered Vehicles by David S. Kircher
3.1.3.1 General — In comparison with the conventional, "uncontrolled," gasoline-powered, spark-ignited,
automotive engine, the uncontrolled diesel automotive engine is a low pollution powerplant. In its uncontrolled
form, the diesel engine emits (in grams per mile) considerably less carbon monoxide and hydrocarbons and
somewhat less nitrogen oxides than a comparable uncontrolled gasoline engine. A relatively small number of
light-duty diesels are in use in the United States.
3.1.3.2 Emissions - Carbon monoxide, hydrocarbons, and nitrogen oxides emission factors for the light -duty,
diesel-powered vehicle are shown in Table 3.1.3-1. These factors are based on tests of several Mercedes 220D
automobiles using a slightly modified version of the Federal light-duty vehicle test procedure.1 '2 Available
automotive diesel test data are limited to these results. No data are available on emissions versus average speed.
Emissions from light-duty diesel vehicles during a calendar year (n) and for a pollutant (p) can be approximately
calculated using:
enp = cipn min (3.1.2-1)
i=n-12
where: enp = Composite emission factor in grams per vehicle mile for calendar year (n) and pollutant (p)
cipn = The 1975 Federal test procedure emission rate for pollutant (p) in grams/mile for the i^1
model year at calendar year (n) (Table 3.1.3-1)
min = The fraction of total light-duty diesel vehicle miles driven by the i^1 model year diesel
light-duty vehicles
Details of this calculation technique are discussed in section 3.1 .2.
The emission factors in Table 3.1 .3-1 for particulates and sulfur oxides were developed using an average sulfur
content fuel in the case of sulfur oxides and the Dow Measuring Procedure on the 1975 Federal test cycle for
participate.1'6
Table 3.1.3-1. EMISSION FACTORS FOR LIGHT-DUTY,
DIESEL-POWERED VEHICLES
EMISSION FACTOR RATING: B
Pollutant
Carbon monoxide3
Exhaust hydrocarbons
Nitrogen oxides3'"3
(NOxasN02)
Particulateb
Sulfur oxidesc
Emission factors,
Pre-1973 model years
g/mi
1.7
0.46
1.6
0.73
0.54
g/km
1.1
0.29
0.99
0.45
0.34
a Estimates are arithmetic mean of tests of vehicles, References 3 through
Band 7.
''Reference 4.
cCalculated using the fuel consumption rate reported in Reference 7 and
assuming the use of a diesel fuel containing 0.20 percent sulfur.
12/75 Internal Combustion Engine Sources 3.1.3-1
-------
References for Section 3.1.3
1. Exhaust Emission Standards and Test Procedures. Federal Register, Part II. 36(128): 12652-12664, July 2,
1971.
2. Control of Air Pollution from Light Duty Diesel Motor Vehicles. Federal Register. Part II. 37(193):
20914-20923, October 4,1972.
3. Springer, K. J. Emissions from a Gasoline - and Diesel-Powered Mercedes 220 Passenger Car. Southwest
Research Institute. San Antonio, Texas. Prepared for the Environmental Protection Agency, Research Triangle
Park, N.C., under Contract Number CPA 7044. June 1971.
4. Ashby, H. A. Final Report: Exhaust Emissions from a Mercedes-Benz Diesel Sedan. Environmental Protection
Agency. Ann Arbor, Mich. July 1972.
5. Test Results from the Last 9 Months — MB220D. Mercedes-Benz of North America. Fort Lee, New Jersey.
Report El 0472. March 1972.
6. Hare, C. T. and K. J. Springer. Evaluation of the Federal Clean Car Incentive Program Vehicle Test Plan.
Southwest Research Institute. San Antonio, Texas. Prepared for Weiner Associates, Incorporated.,
Cockeysville, Md. October 1971.
7. Exhaust Emissions From Three Diesel-Powered Passenger Cars. Environmental Protection Agency, Ann Arbor,
Mich. March 1973. (unpublished report.)
3.1.3-2 EMISSION FACTORS 12/75
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3.1.4 Light-Duty, Gasoline-Powered Trucks by David S. Kircher
and Heavy-Duty, Gasoline-Powered Vehicles and Marcia E. Williams
3.1.4.1 General - This vehicle category consists of trucks and buses powered by gasoline -fueled, spark-ignited
internal combustion engines that are used both for commercial purposes (heavy trucks and buses) and personal
transportation (light trucks). In addition to the use classification, the categories cover different gross vehicle
weight (GVW) ranges. Light trucks range from 0 to 8500 pounds GVW (0 to 3856 kg GVW); heavy-duty vehicles
have GVWs of 8501 pounds (3856 kg) and over. The light-duty truck, because of its unique characteristics and
usage, is treated in a separate category in this revision to AP-42. Previously, light trucks with a GVW of 6000
pounds (2722 kg) or less were included in section 3.1.2 (Light-Duty, Gasoline-Powered Vehicles), and light trucks
with a GVW of between 6001 and 8500 pounds (2722-3855 kg) were included in section 3.1.4 (Heavy-Duty,
Gasoline-Powered Vehicles).
3.1.4.2 Light-Duty Truck Emissions - Because of many similarities to the automobile, light truck emission
factor calculations are very similar to those presented in section 3.1.2. The most significant difference is in the
Federal Test Procedure emission rate.
3.1.4.2.1 . Carbon monoxide, hydrocarbon and nitrogen oxides emissions - The calculation of composite exhaust
emission factors using the FTP method is given by:
enpstw = cipn min vips zipt riptw (3.1.4-1)
i=n-12
where: enpS^w = Composite emission factor in g/mi (g/km) for calendar year (n), pollutant (p), average
speed (s), ambient temperature (t), and percentage cold operation (w)
cipn ~ The FTP (1975 Federal Test Procedure) mean emission factor for the im model year
light-duty trucks during calendar year (n) and for pollutant (p)
mm = The fraction of annual travel by the itn model year light-duty trucks during calendar year
(n)
Vjps = The speed correction factor for the itn model year light-duty trucks for pollutant (p) and
average speed (s)
Zjpt = The temperature correction for the i"1 model year light-duty trucks for pollutant (p) and
ambient temperature (t)
riptw = The hot/cold vehicle operation correction factor for the ith model year light-duty trucks
for pollutant (p), ambient temperature (t), and percentage of cold operation (w)
The data necessary to complete this calculation for any geographic area are presented in Tables 3.1.4-1
through 3.1.4-5. Each of the variables in equation 3.1.4-1 is described in greater detail below. The technique is
illustrated, by example, in section 3.1.2.
12/75 Internal Combustion Engine Sources 3.1.4-1
-------
Table 3.1.4-1. EXHAUST EMISSION FACTORS FOR LIGHT-DUTY,
GASOLINE-POWERED TRUCKS FOR CALENDAR YEAR 1972
EMISSION FACTOR RATING: B
Location
All areas except
high altitude and
California3
High altitudeb
Model
year
Pre-1 968a
1968
1969
1970
1971
1972
Pre-1968
1968
1969
1970
1971
1972
Carbon
monoxide
g/mi
125
66.5
64.3
53.5
53.5
42.8
189
106
98.0
88.0
84.1
84.1
g/km
77.6
41.3
39.9
33.2
33.2
26.6
117
65.8
60.9
54.6
52.2
52.2
Exhaust
hydrocarbons
g/mi
17.0
7.1
5.3
4.8
4.2
3.4
23.3
9.7
6.4
5.5
5.5
5.3
g/krn
10.6
4.4
3.3
3.0
2.6
2.1
14.5
6.0'
4.0
3.4
3.4
3.3
Nitrogen
oxides
g/mi
4.2
4.9
5.3
5.2
5.2
5.3
2.6
3.2
3.1
4.0
3.3
3.6
g/km
2.6
3.0
3.3
3.2
3.2
3.3
1.6
2.0
1.9
2.5
2.0
2.2
References 1 through 4. California emission factors can be estimated as follows:
1. Use pre-1968 factors for all pre-1966 California light trucks.
2. Use 1968 factors for all 1966-1968 California light trucks.
3. For 1969-1972, use the above values multiplied by the ratio of California LDV emission factor:! to low altitude LDV emis-
sion factors (see section 3.1.2).
'•'Based on light-duty emission factors at high altitude compared with light-duty emission factors at low altitude (section 3.1.2).
Table 3-1.4-2. COEFFICIENTS FOR SPEED ADJUSTMENT CURVES FOR LIGHT DUTY TRUCKS3
Location
Low altitude
(Excluding 1966-
1967 Calif.)
California
Low altitude
High altitude
Model
year
1957-1967
1966-1967
1968
1969
1970
1971-1972
1957-1967
1968
1969
1970
1971-1972
„ - P(A + BS + CS2)
vips
Hydrocarbons
A
0.953
0.957
1.070
1 005
0901
0.943
0.883
0.722
0706
0.840
0.787
B
-6.00 x ID-2
-598x 1C-2
-663x 10~2
-6.27 x 1C-2
-570x 10 2
-592x 10-2
-558x 10-2
-4.63 x 10-2
-4.55 x ID-2
-5.33 x ID-2
-4.99 x 10-2
C
5.81 x 10 -"•
563 x 10-"
5 98 x 10 ~4
5.80 x 10 -4
5 59 x 10 ~4
5.67 x 10 -»
5.52 x 10 -"
480x 10 "4
4.84 x 10 ~4
533x 10 -"
499 x 10 -4
Carbon monoxide
A
0967
0981
1.047
1 259
1 267
1 241
0.721
0662
0.628
0835
0.894
B
-6.07 x 10-2
-6.22 x 10-2
-6.52 x 1Q-2
-7.72 x 10-2
-7.72 x 10-2
-752x 10-2
-4.57 x TO-2
-4.23 x 10-2
-4.04x TO'2
-5.24 x TO-2
-5.54 x lO-2
C
5.78 x 10-"
6 19x 10-4
6.01 x 10 ~4
660x 10 -4
6.40 x 10 -4
609x 10~4
4.56 x 10-4
4.33 x 10 -4
4.26 x 10 -4
4 98 x 10 -4
4.99 x 10 -*
v,ps = A + BS
Nitrogen oxides
A
0808
0.844
0888
0.915
0.843
0843
0.602
0.642
0.726
0.614
0.697
B
0 980 x 1 0 ~ 2
0798x 10 -2
0 569 x 10 2
0.432 x TO-2
0.798 x ID'2
0 804 x 10 "2
2027 x ID-2
1.835x 10 ~2
1 403 x 10 ~2
1 978 x lO-2
1.553x 10 -2
aReference 5 Equations should not be extended beyond the range of data (15 to 45 mi/hr) These data are for light-duty vehicles and are assumed applicable to light-
duty trucks
3.1.4-2
EMISSION FACTORS
12/75
-------
Table 3.1.4-3. LOW AVERAGE SPEED CORRECTION
FACTORS FOR LIGHT-DUTY TRUCKS8
Location
Low altitude
(Excluding 1966-
1967 Calif.)
California
Low altitude
High altitude
Model
year
1957-1967
1966-1967
1968
1969
1970
1971-1972
1957-1967
1968
1969
1970
1971-1972
Carbon monoxide
5 mi/hr
(8 km/hr)
2.72
1.79
3.06
3.57
3.60
4.15
2.29
2.43
2.47
2.84
3.00
10 mi/hr
(16 km/hr)
1.57
1.00
1.75
1.86
1.88
2.23
1.48
1.54
1.61
1.72
1.83
Hydrocarbons
5 mi/hr
(8 km/hr)
2.50
1.87
2,96
2.95
2.51
2.75
2.34
2.10
2.04
2.35
2.17
10 mi/hr
(16 km/hr)
1.45
1.12
1.66
1.65
1.51
1.63
1.37
1.27
1.22
1.36
1.35
Nitrogen oxides
5 mi/hr
(8 km/hr)
1.08
1.16
1.04
1.08
1.13
1.15
1.33
1.22
1.22
1.19
1.06
10 mi/hr
(16 km/hr)
1.03
1.09
1.00
1.05
1.05
1.03
1.20
1.18
1.08
1.11
1.02
aDnving patterns developed from CAPE-21 vehicle operation data (Reference 6) were input to the modal emission analysis model
(see section 3.1.2.3). The results predicted by the model (emissions at 5 and 10 mi/hr; 8 and 16 km/hr) were divided by FTP
emission factors for hot operation to obtain the above results. The above data are approximate and represent the best currently
available information.
Table 3.1.4-4. SAMPLE CALCULATION OF FRACTION OF ANNUAL
LIGHT-DUTY TRUCK TRAVEL BY MODEL YEAR3
Age,
years
1
2
3
4
5
6
7
8
9
10
11
12
>13
~™_ — — :
Fraction of total
vehicles in use
nationwide (a)b
0.061
0.095
0.094
0.103
0.083
0.076
0.076
0.063
0.054
0.043
0.036
0.024
0.185
-— — —
Average annual
miles driven (b)
1 5,900
15,000
14,000
13,100
12,200
11,300
10,300
9,400
8,500
7,600
6,700
6,700
4,500
a x b
970
1,425
1,316
1,349
1,013
859
783
592
459
327
241
161
832
Fraction
of annual
travel (m)c
0.094
0.138
0.127
0.131
0.098
0.083
0.076
0.057
0.044
0.032
0.023
0.016
0.081
aVehicles in use by model year as of 1972 (Reference 7).
bReferences 7 and 8.
cm=ab/2ab.
12/75
EMISSION FACTORS
3.1.4-3
-------
Table 3.1.4-5. LIGHT-DUTY TRUCK TEMPERATURE CORRECTION FACTORS AND
HOT/COLD VEHICLE OPERATION CORRECTION FACTORS
FOR FTP EMISSION FACTORS3
Pollutant
Carbon monoxide
Hydrocarbons
Nitrogen oxides
Temperature correction
-------
The equations in Table 3.1.4-2 apply only for the range of the data - from 15 to 45 mi/hr(24 to 72 km/hr).
Because of the need, in some situations, to estimate emissions at very low average speeds, correction factors have
been developed for this purpose. The speed correction factors for 5 and 10 mi/hr (8 and 16 km/hr) presented in
Table 3.1 .4-3 were developed using a method somewhat like that described above, again using the modal emission
model. Because the modal emission model predicts warmed-up vehicle emissions, the use of this model to develop
speed correction factors makes the assumption that a given speed cortection factor applies equally well to hot and
cold vehicle operation.
Temperature Correction Factor (zjpt)- The 1975 FTP requires that emission measurements be made within the
limits of a relatively narrow temperature band (68 to 86° F). Such a band facilitates uniform testing in
laboratories without requiring extreme ranges of temperature control. Present emission factors for motor vehicle
are based on data from the standard Federal test (assumed to be at 75° F). Recently, EPA and the Bureau of
Mines undertook a test program to evaluate the effect of ambient temperatures on motor vehicle exhaust
emissions levels.9 The study indicates that changes in ambient temperature result in significant changes in
emissions during cold start-up operation. Because many Air Quality Control Regions have temperature
characteristics differing considerably from the 68 to 86°F range, the temperature correction factor should be
applied. The corrections factors are expressed in equational form and presented in Table 3.1.4-5 and can be
applied between 20 and 80° F. For temperatures outside this range, the appropriate endpoint correction factor
should be applied.
Hot/Cold Vehicle Operation Correction Factor (rjp^w). The 1975 FTP measures emissions over three types of
driving: a cold transient phase (representative of vehicle start-up after a long engine-off period), a hot transient
phase (representative of vehicle start-up after a short engine-off period), and a stabilized phase (representative of
warmed-up vehicle operation). The weighting factors used in the 1975 FTP are 20 percent, 27 percent, and 53
percent of total miles (time) in each of the three phases, respectively. Thus, when the 1975 FTP emission factors
are applied to a given region for the purpose of assessing air quality, 20 percent of the light-duty trucks in the
area of interest are assumed to be operating in a cold condition, 27 percent in a hot start-up condition, and 53
percent in a hot stabilized condition. For non-catalyst equipped vehicles (all pre-1975 model year vehicles),
emission in the two hot phases are essentially equivalent on a grams per mile (g/km) basis. Therefore, the 1975
FTP emission factor represents 20 percent cold operation and 80 percent hot operation.
Many situations exist in which the application of these particular weighting factors may be inappropriate. For
example, light-duty truck operation in center city areas may have a much higher percentage of cold operation
during the afternoon pollutant emissions peak when work-to-home trips are at a maximum and vehicles have
been standing for 8 hours. The hot/cold vehicle operation correction factor allows the cold operation phase to
range from 0 to 100 percent of total light-duty truck operations. This correction factor is a function of the
percentage of cold operation (w) and the ambient temperature (t). The correction factor is:
w+(100-w)f(t)
riPtw = --- (3 - 1 -4-2)
20+80f(t)
where : f(t) is given in Table 3 . 1 .4-5 .
3.1.4.2.2 Crankcase and evaporative hydrocarbon emissions — Evaporative and crankcase hydrocarbon emissions
are determined using:
fn = himin (3.1.4-3)
i=n-12
where: fn = The combined evaporative and crankcase hydrocarbon emission factor for calendar year (n)
lij = The combined evaporative and crankcase hydrocarbon emission rate for the i^1 model year.
Emission factors for this source are reported in Table 3.1.4-6. The crankcase and evaporative
emissions reported in the table are added together to arrive at this variable.
mjn = The weighted annual travel of the i"1 model year vehicle during calendar year (n)
12/75 EMISSION FACTORS 3.1.4-5
-------
Table 3.1.4-6. CRANKCASE AND EVAPORATIVE HYDROCARBON EMISSION FACTORS FOR
LIGHT-DUTY, GASOLINE-POWERED TRUCKS
EMISSION FACTOR RATING: B
Location
All areas
except high
altitude and
California0
High altitude
Model
years
Pre-1963
1963-1967
1968-1970
1971
1972
Pre-1963
1963-1967
1968-1970
1971-1972
Crankcase
g/mi
4.6
2.4
0.0
0.0
0.0
4.6
2.4
0.0
0.0
emissions3
g/km
2.9
1.5
0.0
0.0
0.0
2.9
1.5
0.0
0.0
Evaporative
g/mi
3.6
3.6
3.6
3.1
3.1
4.6
4.6
4.6
3.9
emissions'3
g/km
2.2
2.2
2.2
1.9
1.9
2.9
2.9
2.9
2.4
aReference 12. Tabulated values were determined by assuming that two-thirds of the light-duty trucks are 6000 Ibs GVW (2700 kg)
and under and that one-third are 6001 to 8500 Ibs GVW (2700 to 3860 kg).
Light-duty vehicle evaporative data (section 3.1.2) and heavy-duty vehicle evaporative data (Table 3.1 4-8) were used to estimate
the values.
cFor California: Evaporative emissions for the 1970 model year are 1.9 g/km (3.1 g/mi). All other model years are the same as
those reported as "All areas except high altitude and California." Crankcase emissions for the pre-1961 California light-duty trucks
are 4.6 g/mi (2.9 g/km) and 1961-1963 models years are 2.4g/mi (1.5 g/km) all post-1963 model year vehicles are 0.0 g/mi (0.0
g/km).
3.1.4.2.3 Sulfur oxide and particulate emissions — Sulfur oxide and particulate emission factors for all model
year light trucks are presented in Table 3.1.4-7. Sulfur oxides factors are based on fuel sulfur content and fuel
consumption. Tire-wear particulate factors are based on automobile test results, a premise necessary because of
the lack of data. Light truck tire wear is likely to result in greater particulate emissions than automobiles because
of larger tires and heavier loads on tires.
Table 3.1.4-7. PARTICULATE AND SULFUR OXIDES
EMISSION FACTORS FOR LIGHT-DUTY,
GASOLINE-POWERED TRUCKS
EMISSION FACTOR RATING: C
Pollutant
Particulate3
Exhaust
Tire wear"3
Sulfur oxides0
(SOxasSO2)
Emissions, Pre-1973 vehicles
g/mi
0.34
0.20
0.18
g/km
0.21
0.12
0.11
aReferences 13 and 14. Based on tests of automobiles.
Reference 14 summarized tests of automotive tire wear particulate. It is
assumed that light-duty truck emissions are similar. The automotive tests
assume a four-tire vehicle. If corrections for vehicles with a greater num-
ber of tires are needed, multiply the above value by the number of tires
and divide by four.
cBased on an average fuel consumption 100 mi/gal (4.3 km/liter) from
Reference 15 and on the use of a fuel with a 0.032 percent sulfur content
from References 17 and 18 and a density of 6.1 Ib/gal (0.73 kg/liter)
from References 17 and 18.
3.1.4-6
Internal Combustion Engine Sources
12/75
-------
3.1.4.3 Heavy-Duty Vehicle Emissions - Emissions research on heavy-duty, gasoline-powered vehicles has been
limited in contrast to that for light-duty vehicles and light-duty trucks. As a result, cold operation correction
factors, temperature correction factors, speed correction factors, idle emission rates, etc. are not available for
heavy-duty vehicles. For some of these variables, however, light-duty vehicle data can be applied to heavy-duty
vehicles. In instances in which light-duty vehicle data are not appropriate, a value of unity if assumed.
3.1.4.3.1 Carbon monoxide, hydrocarbon, and nitrogen oxides emissions - The calculation of heavy-duty,
gasoline-powered vehicle exhaust emission factors can be accomplished using:
cnps
i=n-12
cipn min vips
(3.1.4-4)
where: en»s = Composite emission factor in grams per mile (grams per kilometer) for calendar year (n) and
pollutant (p) and average speed(s)
Cjpn = The test procedure emission rate (Table 3.1.4-8) for pollutant (p) in g/mi (g/km) for the i"1
model year in calendar year (n)
irijn = The weighted annual travel of the i"1 model year vehicles during calendar year (n). The
determination of this variable involves the use of the vehicle year distribution.
ips
speed correction factor for the i"1 model year vehicles for pollutant (p) and average
speed(s)
Table 3.1.4-8. EXHAUST EMISSION FACTORS FOR HEAVY-DUTY,
GASOLINE-POWERED TRUCKS FOR CALENDAR YEAR 1972a
EMISSION FACTOR RATING: B
Location
All areas except
high altitude
High altitude
onlyb
Model
year
Pre-1970
1970
1971
1972
Pre-1970
1970
1971
1972
Carbon
monoxide
g/mi
238
188
188
188
359
299
299
299
g/km
148
117
117
117
223
186
186
186
Exhaust
hydrocarbons
g/mi
35.4
13.8
13.7
13.6
48.6
15.0
14.9
14.8
g/km
22.0
8.6
8.5
8.4
30.2
9.3
9.3
9.2
Nitrogen
oxides
g/mi
6.8
12.6
12.6
12.5
4.1
8.1
8.1
8.1
g/km
4.2
7.8
7.8
7.8
2.5
5.0
5.0
5.0
aData from References 19 and 20.
Based on light-duty emissions at high altitude compared with light-duty emissions at low altitudes.
A brief discussion of the variables presented in the above equation is necessary to help clarify their
formulation and use. The following paragraphs further describe the variables qpn, mjn, and VjpS as they apply to
heavy-duty, gasoline-powered vehicles.
Test procedure emission factor (cipn). The emission factors for heavy-duty vehicles (Table 3.1.4-8) for all areas
are based on tests of vehicles operated on-the-road over the San Antonio Road Route (SARR). The SARR,
located in San Antonio, Texas, is 7.24 miles long and includes freeway, arterial, and local/collector highway
segments. A constant volume sampler is carried on board each of the test vehicles for collection of a
12/75
EMISSION FACTORS
3.1.4-7
-------
proportional part of the exhaust gas from the vehicle. This sample is later analyzed to yield mass emission rates.
Because the SARR is an actual road route, the average speed varies depending on traffic conditions at the time of
the test. The average speed tends to be around 18 mi/hr (29 km/hr) with about 20 percent of the time spent at
idle. The test procedure emission factor is composed entirely of warmed-up vehicle operation. Based on
preliminary analysis of vehicle operation data6, almost all heavy-duty vehicle operation is under warmed-up
conditions.
Weighted annual mileage (mjn). The determination of this variable is illustrated in Table 3.1.4-9. For purposes of
this illustration, nation-wide statistics have been used. Localized data, if available, should be substituted when
calculating the variable mjn for a specific area under study.
Table 3.1.4-9. SAMPLE CALCULATION OF FRACTION OF GASOLINE-POWERED,
HEAVY-DUTY VEHICLE ANNUAL TRAVEL BY MODEL YEAR3
Age,
years
1
2
3
4
5
6
7
8
9
10
11
12
>13
Fraction of total
vehicles in use
nationwide (a)13
0.037
0.070
0.078
0.086
0.075
0.075
0.075
0.068
0.059
0.053
0.044
0.032
0.247
Average annual
miles driven (b)
19,000
18,000
17,000
16,000
14,000
12,000
10,000
9,500
9,000
8,500
8,000
7,500
7,000
a x b
703
1,260
1,326
1,376
1,050
900
750
646
531
451
352
240
1,729
Fraction
of annual
travel (m)c
0.062
0.111
0.117
0.122
0.093
0.080
0.066
0.057
0.047
0.040
0.031
0.021
0.153
aVehicles in use by model year as of 1972 (Reference 7).
^Reference 7.
cm = ab/2ab.
Speed correction factor (vjps). Data based on tests of heavy-duty emissions versus average speed are unavailable.
In the absence of these data, light-duty vehicle speed correction factors are recommended. The data presented in
Tables 3.1.4-10 and Table 3.1.4-11 should be considered as interim heavy-duty vehicle speed correction factors
until appropriate data become available.
3.1.4-8
Internal Combustion Engine Sources
12/75
-------
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12/75
EMISSION FACTORS
3.1.4-9
-------
Table 3.1.4-11. LOW AVERAGE SPEED CORRECTION FACTORS FOR HEAVY-DUTY VEHICLES8
Location
Low
altitude
High
altitude
Model
year
Pre-1970
1970-1972
Pre-1970
1970-1972
Carbon
5 mi/hr
(8 km/hr)
2.72
3.06
2.29
2.43
monoxide
10 mi/hr
(16 km/hr)
1.57
1.75
1.48
1.54
i
Hydrocarbons i Nitrogen oxides
5 mi/hr
(8 km/hr)
2.50
2.96
2.34
2.10
10 mi/hr
(16 km/hr)
1.45
1.66
1.37
1.27
5 mi/hr
(8 km/hr)
1.08
1.04
1.33
1.22
10 mi/hr)
(16 km/hr)
1.03
1.00
1.20
1.18
aDrivmg patterns developed from CAPE-21 vehicle operation data (Reference 6) were input to the modal emission analysis model
(see section 3.1.2.3). The results predicted by the model (emissions at 5 and 10 mi/hr; 8 and 16 krn/hr) were divided by FTP
emission factors for hot operation to obtain the above results. The above data represent the best currently available information
for light-duty vehicles. These data are assumed applicable to heavy-duty vehicles given the lack of better information.
For an explanation of the derivation of these factors, see section 3.1.4.2.1.
In addition to exhaust emission factors, the calculation of evaporative and crankcase hydrocarbon emissions
are determined using:
fn =
i=n-12
himi
in
(3.1.4-5)
where: fn = The combined evaporative and crankcase hydrocarbon emission factor for calendar year (n)
hj = The combined evaporative and crankcase hydrocarbon emission rate for the i"1 model year.
Emission factors for this source are reported in Table 3.1.4-12.
min = The weighted annual travel of the im model year vehicle during calendar year (n)
Table 3.1.4-12. CRANKCASE AND EVAPORATIVE HYDROCARBON EMISSION
FACTORS FOR HEAVY-DUTY, GASOLINE-POWERED VEHICLES
EMISSION FACTOR RATING: B
Location
All areas except
high altitude
and California
California only
High altitude
Model
years
Pre-1968
1968-1972
Pre-1964
1964-1972
Pre-1968
1968-1972
Crankcase hydrocarbon3
g/mi
5.7
0.0
5.7
0.0
5.7
0.0
g/km
3.5
0.0
3.5
0.0
3.5
0.0
Evaporative hydrocarbons'3
g/mi
5.8
5.8
5.8
5.8
7.4
7.4
g/km
3.6
3.6
3.6
3.6
4.6
4.6
aCrankcase factors are from Reference 12.
'•'References 1,21, and 22 were used to estimate evaporative emission factors for heavy -duty vehicles. Equation 3.1.2-6 was used to
calculate g/mi (g/km) values. (Evaporative emission factor = g + kd). The heavy-duty vehicle diurnal evaporative emissions (g) were
assumed to be three times the light-duty vehicle value to account for the larger size fuel tanks used on heavy-duty vehicles. Nine
trips per day (d = number of trips per day) from Reference 6 were used in conjunction with the light-duty vehicle hot soak emis-
sions (k) to yield a total evaporative emission rate in grams per day. This value was divided by 36.2 mi/day (58.3 km/day) from
Reference 7 to obtain the per mile (per kilometer) rate.
3.1.4-10
Internal Combustion Engine Sources
12/75
-------
3.1.4.3.2 Sulfur oxide and particulate emissions - Sulfur oxide and particulate emission factors for all model
year heavy-duty vehicles are presented in Table 3.1.4-13. Sulfur oxides factors are based on fuel sulfur content
and fuel consumption. Tire-wear particulate factors are based on automobile test results — a premise necessary
because of the lack of data. Truck tire wear is likely to result in greater particulate emissions than automobiles
because of larger tires, heavier loads on tires, and more tires per vehicle. Although the factors presented in Table
3.1.4-13 can be adjusted for the number of tires per vehicle, adjustments cannot be made to account for the other
differences.
Table 3.1.4-13. PARTICULATE AND SULFUR OXIDES
EMISSION FACTORS FOR HEAVY-DUTY,
GASOLINE-POWERED VEHICLES
EMISSION FACTOR RATING: B
Pollutant
Particulate
Exhaust3
Tire wear13
Sulfur oxides0
(SOxasS02)
Emissions
g/mi
0.91
0.20T
0.36
g/km
0.56
0.12T
0.22
aCalculated from the Reference 13 value of 12lb/103gal (1.46g/liter)
gasoline. A 6.0 mi/gal (2.6 km/liter) value from Reference 23 was used
to convert to a per kilometer (per mile) emission factor.
"Reference 14. The data from this reference are for passenger cars. In the
absence of specific data for heavy-duty vehicles, they are assumed to be
representative of truck-tire-wear particulate. An adjustment is made for
trucks with more than four tires. T equals the number of tires divided by
four.
cBased on an average fuel consumption of 6.0 mi/gal (2.6 km/liter) from
Reference 23, on a 0.04 percent sulfur content from Reference 16 and
17, and on a density of 6.1 Ib/gal (0.73 kg/liter) from References 16 and
17.
References for Section 3.1.4
1. Automobile Exhaust Emission Surveillance. Calspan Corporation, Buffalo, N.Y. Prepared for Environmental
Protection Agency, Ann Arbor, Mich, under Contract No. 68-01-0435. Publication No. APTD-1544. March
1973.
2. Williams, M. E., J. T. White, L. A. Platte, and C. J. Domke. Automobile Exhaust Emission Surveillance -
Analysis of the FY 72 Program. Environmental Protection Agency, Ann Arbor, Mich. Publication No.
EPA-460/2-74-001. February 1974.
3. A Study of Baseline Emissions on 6,000 to 14,000 Pound Gross Vehicle Weight Trucks. Automobile
Environmental Systems, Inc., Westminister, Calif. Prepared for Environmental Protection Agency, Ann
Arbor, Mich. June 1973,
4. Ingalls, M. N. Baseline Emissions on 6,000 to 14,000 Pound Gross Vehicle Weight Trucks. Southwest
Research Institute, San Antonio, Texas. Prepared for Environmental Protection Agency, Ann Arbor, Mich.
under Contract No. 68-01-0467. Publication No. APTD-1571. June 1973.
5. Smith, M. Development of Representative Driving Patterns at Various Average Route Speeds. Scott Research
Laboratories, Inc., San Bernardino, Calif. Prepared for Environmental Protection Agency, Research Triangle
Park, N.C. February 1974. (Unpublished report.)
12/75 EMISSION FACTORS 3.1.4-'
-------
6. Heavy-duty vehicle operation data (CAPE-21) collected by Wilbur Smith and Associates, Columbia, S.C.,
under contract to Environmental Protection Agency, Ann Arbor, Mich. December 1974.
7. 1972 Census of Transportation. Truck Inventory and Use Survey. U.S. Department of Commerce, Bureau of
the Census, Washington, D.C. 1974.
8. Strate, H. E. Nationwide Personal Transportation Study — Annual Miles of Automobile Travel. Report
Number 2. U.S. Department of Transportation, Federal Highway Administration, Washington, D.C. April
1972.
9. Ashby, H. A., R. C. Stahman, B. H. Eccleston, and R. W. Hum. Vehicle Emissions - Summer to Winter.
(Presented at Society of Automotive Engineers meeting. Warrendale, Pa. October 1974. Paper No. 741053.)
10. Vehicle Operations Survey. Scott Research Laboratories, Inc., San Bernardino, Calif. Prepared under contract
for Environmental Protection Agency, Ann Arbor, Mich., and Coordinating Research Council, New York,
N.Y. December 1971. (unpublished report.)
11. Kunselman, P., H. T. McAdams, C. J. Domke, and M. Williams. Automobile Eixhaust Emission Modal
Analysis Model. Calspan Corporation, Buffalo, N.Y. Prepared for Environmental Protection Agency, Ann
Arbor, Mich, under Contract No. 68-01-0435. Publication No. EPA-460/3-74-005. January 1974.
12. Sigworth, H. W., Jr. Estimates of Motor Vehicle Emission Rates. Environmental Protection Agency, Research
Triangle Park, N.C. March 1971. (Unpublished report.)
13. Control Techniques for Particulate Air Pollutants. U.S. DHEW, National Air Pollution Control Administra-
tion, Washington, D.C. Publication Number AP-51. January 1969.
14. Subramani, J. P. Particulate Air Pollution from Automobile Tire Tread Wear. Ph.D Dissertation. University
of Cincinnati, Cincinnati, Ohio. May 1971.
15. Automobile Facts and Figures. Automobile Manufacturers Association. Washington, D.C. 1971.
16, Shelton, E. M. and C. M. McKinney. Motor Gasolines, Winter 1970-1971. U.S. Department of the Interior,
Bureau of Mines, Bartlesville, Okla. June 1971.
17. Shelton, E. M. Motor Gasolines, Summer 1971. U.S. Department of the Interior, Bureau of Mines,
Bartlesville, Okla. January 1972.
18. Automotive Fuels and Air Pollution. U.S. Department of Commerce, Washington, D.C. March 1971.
19. Ingalls, M. N. and K. J. Springer. In-Use Heavy Duty Gasoline Truck Emissions. Southwest Research
Institute, San Antonio, Texas. Prepared for Environmental Protection Agency, Ann Arbor, Mich. December
1974. (Unpublished report.)
20. Ingalls, M. N. and K. J. Springer. In-Use Heavy Duty Gasoline Truck Emissions, Part 1. Prepared for
Environmental Protection Agency, Research Triangle Park, N.C., under Contract No. EHS 70-113.
Publication No. EPA-460/3-73-002-a. February 1973.
21. Liljedahl, D. R. A Study of Emissions from Light Duty Vehicles in Denver, Houston, and Chicago. Fiscal
Year 1972. Automotive Testing Laboratories, Inc., Aurora, Colo. Prepared for Environmental Protection
Agency, Ann Arbor, Mich. Publication No. APTD 1504.
22. A Study of Emissions from 1966-1972 Light Duty Vehicles in Los Angeles and St. Louis. Automotive
Environmental Systems, Inc., Westminister, Calif. Prepared for Environmental Protection Agency, Ann
Arbor, Mich, under Contract No. 68-01-0455. Publication No. APTD-1505. August 1973.
23. 1973 Motor Truck Facts. Automobile Manufacturers Association, Washington, D.C. 1973.
3.1.4-12 Internal Combustion Engine Sources 12/75
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3.1.5 Heavy-Duty, Diesel-Powered Vehicles revised by David S Kircher
and Marcia E. Williams
3.1.5.1 General1'2 — On the highway, heavy-duty diesel engines are primarily used in trucks and buses. Diesel
engines in any application demonstrate operating principles that are significantly different from those of the
gasoline engine.
3.1.5.2 Emissions — Diesel trucks and buses emit pollutants from the same sources as gasoline-powered vehicles:
exhaust, crankcase blow-by, and fuel evaporation. Blow-by is practically eliminated in the diesel, however,
because only air is in the cylinder during the compression stroke. The low volatility of diesel fuel along with the
use of closed injection systems essentially eliminates evaporation losses in diesel systems.
Exhaust emissions from diesel engines have the same general characteristics of auto exhausts. Concentrations
of some of the pollutants, however, may vary considerably. Emissions of sulfur dioxide are a direct function of
the fuel composition. Thus, because of the higher average sulfur content of diesel fuel (0.20 percent S) as
compared with gasoline (0.035 percent S), sulfur dioxide emissions are relatively higher from diesel exhausts.3-4
Because diesel engines allow more complete combustion and use less volatile fuels than spark-ignited engines,
their hydrocarbon and carbon monoxide emissions are relatively low. Because hydrocarbons in diesel exhaust
represent largely unburned diesel fuel, their emissions are related to the volume of fuel sprayed into the
combustion chamber. Both the high temperature and the large excesses of oxygen involved in diesel combustion
are conducive to high nitrogen oxide emission, however.6
Particulates from diesel exhaust are in two major forms — black smoke and white smoke. White smoke is
emitted when the fuel droplets are kept cool in an environment abundant in oxygen (cold starts). Black smoke is
emitted when the fuel droplets are subjected to high temperatures in an environment lacking in oxygen (road
conditions).
Emissions from heavy-duty diesel vehicles during a calendar year (n) and for a pollutant (p) can be
approximately calculated using:
n
e
nps ~ 2-r cipnvips (3.1.5-1)
i=n-12
where: enpS = Composite emission factor in g/mi (g/km) for calendar year (n), pollutant (p), and average
speed (s)
cipn = The emission rate in g/mi (g/km) for the i^1 model year vehicles in calendar year (n) over a
transient urban driving schedule with an average speed of approximately 18 mi/hr (29
km/hr)
vips = The speed correction factor for the im model year heavy-duty diesel vehicles for pollutant
(p) and average speed (s)
Values for Cjpn are given in Table 3,1.5-1. These emission factors are based on tests of vehicles on-the-road
over the San Antonio Road Route (SARR). The SARR, located in San Antonio, Texas, is 7.24 miles long and
includes freeway, arterial, and local/collector highway segments.7 A constant volume sampler is carried on board
12/75 Internal Combustion Engine Sources 3.1.5-1
-------
each test vehicle for collection of a proportional part of the vehicle's exhaust. This sample is later analyzed to
yield mass emission rates. Because the SARR is an actual road route, the average speed varies depending on traffic
conditions at the time of the test. The average speed, however, tends to be around 18 mi/hr (29 km/hr), with
about 20 percent of the time spent at idle. The test procedure emission factor is composed entirely of warmed-up
vehicle operation. Based on a preliminary analysis of vehicle operation data, heavy-duty vehicles operate primarily
(about 95 percent) in a warmed-up condition.
Table 3.1.5-1. EMISSION FACTORS FOR HEAVY-DUTY, DIESEL-POWERED VEHICLES
(ALL PRE-1973 MODEL YEARS) FOR CALENDAR YEAR 1972
EMISSION FACTOR RATING: B
Pollutant
Particulatec
Sulfur oxidesc'd
(SOX asSO2)
Carbon monoxide
Hydrocarbons
Nitrogen oxides
(NOxasN02)
Aldehydes0
(as HCHO)
Organic acidsc
Truck emissions3
g/mi
1.3
2.8
28.7
4.6
20.9
0.3
0.3
g/km
0.81
1.7
17.8
2.9
13.0
0.2
City bus emissions"
g/mi
1.3
2.8
21.3
4.0
21.5
0.3
0.2 > 0.3
g/km
0.81
1.7
13.2
2.5
13.4
0.2
0.2
aTruck emissions are based on over-the-road sampling of diesel trucks by Reference 7. Sampling took place on the San Antonio
(Texas) Road Route (SARR), which is 7.24 miles (11.7 kilometers) long and includes freeway, arterial, and local/collector high-
way segments. Vehicles average about 18 mi/hr (29 km/hr) over this road route.
''Busemission factors are also based on the SARR. 13-Mode emission data from Reference 6 were converted to SARR values using
cycle-to-cycle conversion factors from Reference 8.
cReference 6. Tire wear particulate not included in above particulate emission factors. See tire wear paiticulate, heavy-duty gaso-
line section.
^Data based on assumed fuel sulfur content of 0.20 percent. A fuel economy of 4.6 mi/gal (2.0 km/liter) was used from Reference
9.
The speed correction factor, vjps, can be computed using data in Table 3.1.5-2. Table 3.1.5-2 gives heavy-duty
diesel HC, CO, and NOX emission factors in grams per minute for the idle mode, an urban transient mode with
average speed of 18 mi/hr (29 km/hr), and an over-the-road mode with an average speed of approximately 60
mi/hr (97 km/hr). For average speeds less than 18 mi/hr (29 km/hr), the correction factor is:
vips
18
Urban + (~ -1) Idle
O
Urban
(3.1.5-2)
where: s is the average speed of interest (in mi/hr), and the urban and idle values (in g/min) are obtained from
Table 3.1.5-2. For average speeds above 18 mi/hr (29 km/hr), the correction factor is:
vips
18
42S [(60-S) Urban + (S-l 8) Over the Road]
Urban
(3.1.5-3)
Where: S is the average speed (in mi/hr) of interest. Urban and over-the-road values (in g/min) are obtained from
Table 3.1.5-2. Emission factors for heavy-duty diesel vehicles assume all operation to be under warmed-up vehicle
conditions. Temperature correction factors, therefore, are not included because ambient temperature has minimal
effects on warmed-up operation.
3.1.5-2
EMISSION FACTORS
12/75
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Table 3.1.5-2. EMISSION FACTORS FOR HEAVY-DUTY DIESEL VEHICLES
UNDER DIFFERENT OPERATING CONDITIONS
EMISSION FACTOR RATING: B
! Emission factors? g/min
i
Pollutant j
Carbon monoxide
Hydrocarbons :
Nitrogen oxides
(NOxasNO2)
Idle
0.64
0.32
1.03
Urban [18mi/hr (29 km/hr)]
8.61
1.38
6.27
Over-the-road
[60 mi/hr (97 km/hr]
5.40
2.25
28.3
aReference 7. Computed from data contained in the reference.
References for Section 3.1.5
1. The Automobile and Air Pollution: A Program for Progress. Part 11. U.S. Department of Commerce,
Washington, D.C. December 1967. p. 34.
2. Control Techniques for Carbon Monoxide, Nitrogen Oxides, and Hydrocarbons from Mobile Sources. U.S,.
DHEW, PHS, EHS, National Air Pollution Control Administration. Washington, D.C. Publication Number
AP-66. March 1970. p. 2-9 through 2-11.
3. McConnel, G. and H. E. Howels. Diesel Fuel Properties and Exhaust Gas-Distant Relations? Society of
Automotive Engineers. New York, N.Y. Publication Number 670091. January 1967.
4. Motor Gasolines, Summer 1969. Mineral Industry Surveys. U.S. Department of the Interior, Bureau of Mines.
Washington, D.C. Petroleum Products Survey Number 63.1970. p. 5.
5. Hum, R. W. The Diesel Fuel Involvement in Air Pollution. (Presented at the National Fuels and Lubricants
Meeting, New York, N.Y. September 17-18, 1969).
6. Young, T. C. Unpublished emission factor data on diesel engines. Engine Manufacturers Association Emission
Standards Committee, Chicago, 111. October 16, 1974.
7. Ingalls, M. N. and K. J. Springer. Mass Emissions from Diesel Trucks Operated over a Road Course. Southwest
Research Institute, San Antonio, Texas. Prepared for Environmental Protection Agency. Ann Arbor, Mich.
under Contract No. 68-01-2113. Publication No. EPA-460/3-74-017. August 1974.
8. Heavy-Duty Vehicle Interim Standards Position Paper. Environmental Protection Agency, Emission Control
Technology Division, Ann Arbor, Mich. January 1975.
9. Truck and Bus Fuel Economy. U.S. Department of Transportation, Cambridge, Mass, and Environmental
Protection Agency, Ann Arbor, Mich. Report No. 7 of seven panel reports. January 10, 1975.
12/75 Internal Combustion Engine Sources 3.1.5-3
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3.1.6 Gaseous-Fueled Vehicles by David S. Kircher
3.1.6.1 General - Conversion of vehicles to gaseous fuels has been practiced for many years. In the past the
principal motivation for the conversion has been the economic advantage of gaseous fuels over gasoline rather
than lower air pollutant emission levels that result from their use. Recently, however, conversions have been made
for air pollution control as well as for lower operating cost. Liquified petroleum gas (LPG), the most common
form of gaseous fuel for vehicles, is currently used to power approximately 300,000 vehicles in the United States.
Natural gas, in the form of compressed natural gas (CNG) or liquified natural gas (LNG), is being used nationally
to power about 4,000 vehicles.1 Of the two natural gas fuels, CNG is the most common. Natural gas conversions
are usually dual fuel systems that permit operation on either gaseous fuel (CNG or LNG) or gasoline.
3.1.6.2 Emissions - Tables 3.1.6-1 and 3.1.6-2 contain emission factors for light- and heavy-duty vehicles
converted for either gaseous fuel or dual fuel operation. The test data used to determine the average light duty
emission factors were based on both the 1972 Federal test procedure and the earlier seven-mode method. ^ >8
These test data were converted to the current Federal test procedure^ using conversion factors determined
empirically.10'11 This conversion was necessary to make the emission factors for these vehicles consistent with
emission factors reported in previous sections of this chapter.
Heavy-duty vehicle emission factors (Table 3.1.6-2) are based on tests of vehicles on an experimental
dynamometer test cycle^ and on the Federal test procedure. Emissions data for heavy-duty vehicles are limited to
tests of only a few vehicles. For this reason the factors listed in table 3.1.6-2 are only approximate indicators of
emissions from these vehicles.
Emission data on gaseous-powered vehicles are limited to dynamometer test results. Deterioration factors and
speed correction factors are not available. The data contained in the tables, therefore, are emission factors for
in-use vehicles at various mileages rather than emission rates (as defined in section 3.1.2).
Emission factors for a particular population of gaseous-fueled vehicles can be determined using the relation-
ship:
e
cnpwc
n + 1
V r
LJ
i=n- 12
where: enpwc = Emission factor is grams per mile (or g/km) for calendar year (n), pollutant (p), vehicle weight
(w) (light- or heavy-duty), and conversion fuel system (c) (e.g. LPG)
Cj = The test cycle emission factor (Tables 3.1.6-1 and 3.1.6-2) for pollutant (p) for the i^1 model
year vehicles
fj = The fraction of total miles driven by a population of gaseous-fueled vehicles that are driven by
the itn model year vehicles
Carbon monoxide, hydrocarbon, and nitrogen oxides emission factors are listed in the tables. Particulates and
sulfur oxides are not listed because of the lack of test data. Because stationary external combustion of gaseous
fuel results in extremely low particulate and sulfur oxides, it is reasonable to assume that the emissions of these
pollutants from gaseous-fueled vehicles are negligible.
4/73 Internal Combustion Engine Sources 3.1.6-1
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Table 3.1.6-1. EMISSION FACTORS BY MODEL YEAR FOR LIGHT-DUTY
VEHICLES USING LPG, LPG/DUAL FUEL, OR CNG/DUAL FUEL3
EMISSION FACTOR RATING: B
Fuel and
model year
LPG
Pre-1970b
1970 through
1972C
LPG/Dual fueld
Pre-1973
CNG/Duai fuel6
Pre-1973
Carbon
monoxide
g/mi
11
3.4
7.8
9.2
g/km
6.8
2.1
4.8
5.7
Exhaust
hydrocarbons
g/mi
1.8
0.67
2.4
1.5
g/km
1.1
0.42
1.5
0.93
N itrogen
oxides (NOX as NO2)
g/mi
3.2
2.8
3.4
2.8
g/km
2.0
1.7
2.1
1.7
a References 1 through 5.
k Emission factors are based on tests of 1968 and 1969 model year vehicles. Sufficient data for earlier modelsare not
available.
0 Based on tests of 1970 model year vehicles. No attempt was made to predict the emissions resulting from the
conversion of post 1974 model year vehicles to gaseous fuels. It is likely that 1973 and 1 974 model year vehicles
converted to gaseous fuels will emit pollutant quantities similar to those emitted by 1972 vehicles with the
possible exception of nitrogen oxides.
^ The dual fuel system represents certain compromises in emission performance to allow the flexibility of operation
on gaseous or liquid (gasoline) fuels. For this reason their emission factors are listed separately from vehicles using
LPG only.
e Based on tests of 1968 and 1969 model year vehicles. It is likely that 1973 and 1974 model year vehicles will emit
similar pollutant quantities to those listed with the possible exception of nitrogen oxides. Mo attempt was made to
estimate 1975 and later model year gaseous-fueled-vehicle emissions.
Table 3.1.6-2. EMISSION FACTORS FOR HEAVY-DUTY
VEHICLES USING LPG OR CNG/DUAL FUEL
EMISSION FACTOR RATING: C
Pollutant
Carbon monoxide
Exhaust
hydrocarbons
Nitrogen oxides
(NOxasN02)
Emissions (all model years)3
LPGb,c
g/mi
4.2
2.4
2.8
g/km
2.6
1.5
1.7
CNG/dual fueia
g/mi
7.5
2.2
5.8
g/km
4.6
1.4
3.6
aTest results are for 1959 through 1970 model years. These results
are assumed to apply to all future heavy-duty vehicles based on
present and future emission standards.
b References 2 and 4.
c LPG values for heavy-duty vehicles are based on a limited number
of tests of vehicles tuned for low emissions. Vehicles converted to
LPG solely for economic reasons gave much higher emission values.
For example, eleven vehicles (1950 through 1963) tested in Refer-
ence 6 demonstrated average emissions of 160 g/mi (99 g/km) of
carbon monoxide, 8.5 g/mi (5.3 g/km) of hydrocarbons, and 4.2
g/mil (2.6 g/km) of nitrogen oxides.
d Reference 5.
3.1.6-2
EMISSION FACTORS
4/73
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References for Section 3.1.6
1. Conversion of Motor Vehicles to Gaseous Fuel to Reduce Air Pollution. U.S. Environmental Protection
Agency, Office of Air Programs. Washington, D.C. April 1972.
2. Fleming, R.D. et al. Propane as an Engine Fuel for Clean Air Requirements. J. Air Pol. Control Assoc.
22:451-45 8. June 1972.
3. Genslak, S.L. Evaluation of Gaseous Fuels for Automobiles. Society of Automotive Engineers, Inc. New
York,N.Y. Publication Number 720125. January 1972.
4. Eshelman, R.H. LP Gas Conversion. Automotive Industries. Reprinted by Century LP-Gas Carburetion,
Marvel-Schebler. Decatur, III.
5. Pollution Reduction with Cost Savings. General Services Administration. Washington, D.C. 1971.
6. Springer, K.J. An Investigation of Emissions from Trucks above, 6,000-lb GVW Powered by Spark-Ignited
Engines. Southwest Research Institute. San Antonio, Texas. Prepared for the U.S. Public Health Service.
Washington, D.C., under Contract Number PH 86-67-72. March 1969.
7. Control of Air Pollution from New Motor Vehicles and New Motor Vehicle Engines. Federal Register. Part II.
33(219): 17288-17313, November 10, 1970.
8. Control of Air Pollution from New Motor Vehicles and New Motor Vehicle Engines. Federal Register. Part II.
33(219): 17288-17313, November 10, 1970.
9. Exhaust Emission Standards and Test Procedures. Federal Register. Part II. 56(128): 12652-12663, July 2,
1971.
10. Sigworth, H.W., Jr. Unpublished estimates of motor vehicle emission rates. Environmental Protection
Agency. Research Triangle Park, N.C. March 1971.
11. Study of Emissions from Light-Duty Vehicles in Six Cities. Automotive Environmental Systems, Inc. San
Bernadino, Calif. Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under
Contract Number 68-04-0042. June 1972.
4/73 Internal Combustion Engine Sources 3.1.6-3
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3.1.7 Motorcycles by David S. Kircher
3.1.7.1 General - Motorcycles, which are not, generally, considered an important source of air pollution, have
become more popular and their numbers have been steadily increasing in the last few years. Sales grew at an
annual rate of 20 percent from 1965 to 1971 ^ The majority of motorcycles are powered by either 2- or 4-stroke,
air-cooled engines; however, water-cooled motorcycles and Wankel-powered motorcycles have recently been
introduced. Until recently the predominant use of 4-stroke motorcycles was on-high way and the 2-stroke variety
was off-highway. This difference in roles was primarily a reflection of significant weight and power variations
between available 2- and 4-stroke vehicles. As light-weight 4-strokes and more powerful 2-strokes become
available the relative number of motorcycles in each engine category may change. Currently the nationwide
population of motorcycles is approximately 38 percent 2-stroke and 62 percent 4-stroke. Individual motorcycles
travel, on the average, approximately 4000 miles per year.1 These figures, along with registration statistics, enable
the rough estimation of motorcycle miles by engine category and the computation of resulting emissions.
3.1.7.2 Emissions — The quantity of motorcycle emission data is rather limited in comparison with the data
available on other highway vehicles. For instance, data on motorcycle average speed versus emission levels are not
available. Average emission factors for motorcycles used on highways are reported in Table 3.1.7-1. These data,
from several test vehicles, are based on the Federal light-duty vehicle test procedure.2 The table illustrates
differences in 2-stroke and 4-stroke engine emission rates. On a per mile basis, 2-stroke engines emit nearly five
times more hydrocarbons than 4-stroke engines. Both engine categories emit somewhat similar quantities of
carbon monoxide and both produce low levels of nitrogen oxides.
4/73 Internal Combustion Engine Sources 3.1.7-1
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Table 3.1.7-1. EMISSION FACTORS FOR MOTORCYCLES3
EMISSION FACTOR RATING: B
Pollutant
Carbon monoxide
Hydrocarbons
Exhaust
Crankcase"
Evaporative0
Nitrogen oxides
(NOX as N02)
Participates
Sulfur oxides0'
(S02)
Aldehydes
(RCHOasHCHO)
Emissions
2-stroke engine
g/mi
27
16
—
0.36
0.12
0.33
0.038
0.11
g/km
17
9.9
—
0.22
0.075
0.21
0.024
0.068
4-stroke engine
g/mi
33
2.9
0.60
0.36
0.24
0.046
0.022
0.047
g/km
20
1.8
0.37
0.22
0.15
0.029
0.014
0.029
a Reference 1.
k Most 2-stroke engines use crankcase induction and produce no crankcase losses.
c Evaporative emissions were calculated assuming that carburetor losses were negligible. D iurnal
breathing of the fuel tank ( a function of fuel vapor pressure, vapor space in the tank, and
diurnal temperature variation) was assumed to account for all the evaporative lossies associated
with motorcycles. The value presented is based on average vapor pressure, vapor space, and
temperature variation.
^ Calculated using a 0.043 percent sulfur content (by weight) for regular fuel used in 2-stroke
engines and 0.022 percent sulfur content (by weight) for premium fuel used in 4-stroke engines.
References for Section 3.1.7
1. Hare, C.T. and K.J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Part III, Motorcycles. Final Report. Southwest Research Institute. San
Antonio, Texas. Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under
Contract Number EHS 70-108. March 1973.
2. Exhaust Emission Standards and Test Procedures. Federal Register. #5(128): 12652-12663, July 2, 1971.
3.1.7-2
EMISSION FACTORS
4/73
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3.2 OFF-HIGHWAY, MOBILE SOURCES
The off-highway category of internal combustion engines embraces a wide range of mobile and semimobile
sources. Emission data are reported in this section on the following sources: aircraft; locomotives; vessels (inboard
and outboard); and small general utility engines, such as those used in lawnmowers and minibikes. Other sources
that fall into this category, but for which emission data are not currently available, include: snowmobiles,
all-terrain vehicles, and farm and construction equipment. Data on these sources will be added to this chapter in
future revisions.
3.2.1 Aircraft by Charles C. Masser
3.2.1.1 General - Aircraft engines are of two major categories; reciprocating (piston) and gas turbine.
The basic element in the aircraft piston engine is the combustion chamber, or cylinder, in which mixtures of
fuel and air are burned and from which energy is extracted through a piston and crank mechanism that drives a
propeller. Th; majority of aircraft piston engines have two or more cylinders and are generally classified
according to their cylinder arrangement - either "opposed" or radial." Opposed engines are installed in most
light or utility aircraft; radial engines are used mainly in large transport aircraft.
The gas turbine engine in general consists of a compressor, a combustion chamber, and a turbine. Air entering
the forward end of the engine is compressed and then heated by burning fuel in the combustion chamber. The
major portion of the energy in the heated air stream is used for aircraft propulsion. Part of the energy is expended
in driving the turbine, which in turn drives the compressor. Turbofan and turboshaft engines use energy from the
turbine for propulsion; turbojet engines use only the expanding exhaust stream for propulsion.
The aircraft classification system used is listed in Table 3.2.1-1. Both turbine aircraft and piston engine
aircraft have been further divided into sub-classes depending on the size of the aircraft and the most commonly
used engine for that class. Jumbo jets normally have approximately 40,000 pounds maximum thrust per engine,
and medium-range jets have about 14,000 pounds maximum thrust per engine. For piston engines, this division is
more pronounced. The large transport piston engines are in the 500 to 3,000 horsepower range, whereas the small
piston engines develop less than 500 horsepower.
4/73 Internal Combustion Engine Sources 3.2.1-1
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Table 3.2.1-1. AIRCRAFT CLASSIFICATION
Aircraft class
Jumbo jet
Long-range jet
Medium-range jet
Air carrier
turboprop
Business jet
General aviation
turboprop
General aviation
piston
Piston transport
Helicopter
Military transport
Military jet
Military piston
Representative aircraft
Boeing 747
Lockheed L-1011
McDonald Douglas DC-10
Boeing 707
McDonald Douglas DC-8
Boeing 727
Boeing 737
McDonald Douglas DC-9
Convair 580
Electra L-188
Fairchild Miller FH-227
Gates Learjet
Lockheed Jetstar
-
Cessna 210
Piper 32-300
Douglas DC-6
Sikorsky S-61
Vertol 107
Engines
per
aircraft
4
3
3
4
4
3
2
2
2
4
2
2
4
-
1
1
4
2
2
Engine
commonly used
Pratt & Whitney
JT-9D
Pratt & Whitney
JT-3D
Pratt & Whitney
JT-8D
Allison 501-D13
General Electric
CJ610
Pratt & Whitney
JT-12A
Pratt & Whitney
PT-6A
Teledyne-Continen-
tal 0-200
Lycoming 0-320
Prat! & Whitney
R-2800
General Electric
CT-58
Allison T56A7
General Electric
J-79
Continental J-69
Curtiss-Wright
R-1820
3.2.1-2
EMISSION FACTORS
4/73
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3.2.1.2 Landing and Takeoff Cycle - A landing-takeoff (LTO) cycle includes all normal operation modes
performed by an aircraft between the time it descends through an altitude of 3,500 feet (1,100 meters) on its
approach and the time it subsequently reaches the 3,500 foot (1,100 meters) altitude after take. It should be
made clear that the term "operation" used by the Federal Aviation Administration to describe either a landing or
a takeoff is not the same as the LTO cycle. Two operations are involved in one LTO cycle. The LTO cycle
incorporates the ground operations of idle, taxi, landing run, and takeoff run and the flight operations of takeoff
and climbout to 3,500 feet (1,100 meters) and approach from 3,500 feet (1,100 meters) to touchdown
Each class of aircraft has its own typical LTO cycle. In order to determine emissions, the LTO cycle is
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taxi-idle. Each of these modes has its share of time in the LTO cycle. Table 3.2.1-2 shows typical operating time
in each mode for the various types of aircraft classes during periods of heavy activity at a large metropolitan
airport. Emissions factors for the complete LTO cycle presented in Table 3.2.1-3 were determined using the
typical times shown in Table 3.2.1-2.
Table 3.2.1-2. TYPICAL TIME IN MODE FOR LANDING TAKEOFF CYCLE
AT A METROPOLITAN AIRPORT3
Aircraft
Jumbo jet
Long range
jet
Medium range
jet
Air carrier
turboprop
Business jet
General avia-
tion turboprop
General aviation
piston
Piston transport
Helicopter
Military transport
Military jet
Military piston
Time in mode, minutes
Taxi-idle
19.00
19.00
19.00
19.00
6.50
19.00
12.00
6.50
3.50
19.00
6.50
6.50
Takeoff
0.70
0.70
0.70
0.50
0.40
0.50
0.30
0.60
0
0.50
0.40
0.60
Climbout
2.20
2.20
2.20
2.50
0.50
2.50
4.98
5.00
6.50
2.50
0.50
5.00
Approach
4.00
4.00
4.00
4.50
1.60
4.50
6.00
4.60
6.50
4.50
1.60
4.60
Taxi-idle
7.00
7.00
7.00
7.00
6.50
7.00
4.00
6.50
3.50
7.00
6.50
6.50
References 1 and 2.
4/73
Internal Combustion Engine Sources
3.2.1-3
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EMISSION FACTORS
4/73
-------
3.2.1.3 Modal Emission Factors - In Table 3.2.1-4 a set of modal emission factors by engine type are given for
carbon monoxide, total hydrocarbons, nitrogen oxides, and solid participates along with the fuel flow rate per
engine for each LTO mode. With this data and knowledge of the time-m-mode. it is possible to construct any
LTO cycle or mode and calculate a more accurate estimate of emissions for the situation that exists at a specific
airport. This capability is especially important for estimating emissions during the taxi-idle mode when large
amounts of carbon monoxide and hydrocarbons are emitted. At smaller commercial airports the taxi-idle time
will be less than at the larger, more congested airports.
4/73 Internal Combustion Engine Sources 3.2.1-5
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EMISSION FACTORS
4/73
-------
References for Section 3.2.1
1. Nature and Control of Aircraft Engine Exhaust Emissions. Northern Research and Engineering Corporation.
Cambridge, Mass. Prepared for National Air Pollution Control Administration. Durham. N.C., under Contract
Number PH22-68-27. November 1968.
2. The Potential Impact of Aircraft Emissions upon Air Quality. Northern Research and Engineering
Corporation, Cambridge, Mass. Prepared for the Environmental Protection Agency, Research Triangle Park,
N.C., under Contract Number 68-02-0085. December 1971.
3. Assessment of Aircraft Emission Control Technology. Northern Research and Engineering Corporation.
Cambridge, Mass. Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under
Con tract Number 68-04-0011. September 1971.
4. Analysis of Aircraft Exhaust Emission Measurements. Cornell Aeronautical Laboratory Inc. Buffalo, N.Y.
Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under Contract Number
68-04-0040. October 1971.
5. Private communication with Dr. E. Karl Bastress. 1KOR Incorporated. Burlington, Mass. November 1972.
4/73 Internal Combustion Engine Sources 3.2.1-9
-------
-------
3.2.2 Locomotives
by David S. Kircher
3.2.2.1 General - Railroad locomotives generally follow one of two use patterns: railyard switching or road-haul
service. Locomotives can be classified on the basis of engine configuration and use pattern into five categories:
2-stroke switch locomotive (supercharged), 4-stroke switch locomotive, 2-stroke road service locomotive
(supercharged), 2-stroke road service locomotive (turbocharged), and 4-stroke road service locomotive.
The engine duty cycle of locomotives is much simpler than many other applications involving diesel internal
combustion engines because locomotives usually have only eight throttle positions in addition to idle and
dynamic brake. Emission testing is made easier and the results are probably quite accurate because of the
simplicity of the locomotive duty cycle.
3.2.2.2 Emissions — Emissions from railroad locomotives are presented two ways in this section. Table 3.2.2-1
contains average factors based on the nationwide locomotive population breakdown by category. Table 3.2.2-2
gives emission factors by locomotive category on the basis of fuel consumption and on the basis of work output
(horsepower hour).
The calculation of emissions using fuel-based emission factors is straightforward. Emissions are simply the
product of the fuel usage and the emission factor. In order to apply the work output emission factor, however, an
Table 3.2.2-1. AVERAGE LOCOMOTIVE
EMISSION FACTORS BASED
ON NATIONWIDE STATISTICS3
Pollutant
Particulatesc
Sulfur oxidesd
(SOX as S02>
Carbon monoxide
Hydrocarbons
Nitrogen oxides
(NOxasN02)
Aldehydes
(as HCHO)
Organic acidsc
Average emissions'3
lb/103gal
25
57
130
94
370
5.5
7
kg/103 liter
3.0
6.8
16
11
44
0.66
0.84
Reference 1.
Based on emission data contained in Table 3.2 2-2
and the breakdown of locomotive use by engine
category in the United States in Reference 1.
Data based on highway diesel data from Reference
2 No actual locomotive participate test data are
available.
Based on a fuel sulfur content of 0 4 percent from
Reference 3
4/73
Internal Combustion Engine Sources
3.2.2-1
-------
Table 3.2.2-2. EMISSION FACTORS BY LOCOMOTIVE ENGINE
CATEGORY3
EMISSION FACTOR RATING: B
Pollutant
Carbon monoxide
lb/103gal
kg/103 liter
g/hphr
g/metric hphr
Hydrocarbon
Ib/K^gal
kg/103 liter
g/hphr
g/metric hphr
Nitrogen oxides
(NOxasN02)
lb/103 gal
kg/103 liter
g/hphr
g/metric hphr
Engine category
2-Stroke
supercharged
switch
84
10
3.9
3.9
190
23
8.9
8.9
250
30
11
11
4-Stroke
switch
380
46
13
13
146
17
5.0
5.0
490
59
17
17
2-Stroke
supercharged
road
66
7.9
1.8
1.8
148
18
4.0
4.0
350
42
9.4
9.4
2-Stroke
turbocharged
road
160
19
4.0
4.0
28
3.4
0.70
0.70
330
40
8.2
8.2
4-Stroke
road
180
22
4.1
4.1
99
12
2.2
2.2
470
56
10
10
a Use average factors (Table 3.2.2-1) for pollutants not listed in this table.
additional calculation is necessary. Horsepower hours can be obtained using the following equation:
w=lph
where: w = Work output (horsepower hour)
1 = Load factor (average power produced during operation divided by available power)
p = Available horsepower
h = Hours of usage at load factor (1)
After the work output has been determined, emissions are simply the product of the work output and the
emission factor. An approximate load factor for a line-haul locomotive (road service) is 0.4; a typical switch
engine load factor is approximately 0.06.1
References for Section 3.2.2
1. Hare, C.T. and K.J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Part 1. Locomotive Diesel Engines and Marine Counterparts. Final Report.
Southwest Research Institute. San Antonio, Texas Prepared for the Environmental Protection Agency,
Research Triangle Park, N.C., under Contract Number EHA 70-108. October 1972.
2. Young, T.C. Unpublished Data from the Engine Manufacturers Association. Chicago, 111. May 1970.
3. Hanley, G.P. Exhaust Emission Information on Electro-Motive Railroad Locomotives and Diesel Engines.
General Motors Corp. Warren, Mich. October 1971.
3.2.2-2
EMISSION FACTORS
4/73
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3.2.3 Inboard-Powered Vessels Revised by David S. Kircher
3.2.3.1 General - Vessels classified on the basis of use will generally fall into one of three categories: commercial,
pleasure, or military. Although usage and population data on vessels are, as a rule, relatively scarce, information on
commercial and military vessels is more readily available than data on pleasure craft. Information on military
vessels is available in several study reports,1"5 but data on pleasure craft are limited to sales-related facts and
figures.6-10
Commercial vessel population and usage data have been further subdivided by a number of industrial and
governmental researchers into waterway classifications' '"16 (for example, Great Lakes vessels, river vessels, and
coastal vessels). The vessels operating in each of these wateiway classes have similar characteristics such as size,
weight, speed, commodities transported, engine design (external or internal combustion), fuel used, and distance
traveled. The wide variation between classes, however, necessitates the separate assessment of each of the waterway
classes with respect to air pollution.
Information on military vessels is available from both the U.S. Navy and the U.S. Coast Guard as a result of
studies completed recently. The U.S. Navy has released several reports that summarize its air pollution assessment
work.3"5 Emission data have been collected in addition to vessel population and usage information. Extensive
study of the air pollutant emissions from U.S. Coast Guard watercraft has been completed by the U.S. Department
of Transportation. The results of this study are summarized in two reports.1 "2 The first report takes an in-depth
look at population/usage of Coast Guard vessels. The second report, dealing with emission test results, forms the
basis for the emission factors presented in this section for Coast Guard vessels as well as for non-military diesel
vessels.
Although a large portion of the pleasure craft in the U.S. are powered by gasoline outboard motors (see section
3.2.4 of this document), there are numerous larger pleasure craft that use inboard power either with or without
"out-drive" (an outboard-like lower unit). Vessels falling into the inboard pleasure craft category utilize either Otto
cycle (gasoline) or diesel cycle internal combustion engines. Engine horsepower varies appreciably from the small
"auxiliary" engine used in sailboats to the larger diesels used in yachts.
3.2.3.2 Emissions
Commercial vessels. Commercial vessels may emit air pollutants under two major modes of operation:
underway and at dockside (auxiliary power).
Emissions underway are influenced by a great variety of factors including power source (steam or diesel), engine
size (in kilowatts or horsepower), fuel used (coal, residual oil, or diesel oil), and operating speed and load.
Commercial vessels operating within or near the geographic boundaries of the United States fall into one of the
three categories of use discussed above (Great Lakes, rivers, coastline). Tables 3.2.3-1 and 3.2.3-2 contain emission
information on commercial vessels falling into these three categories. Table 3.2.3-3 presents emission factors for
diesel marine engines at various operating modes on the basis of horsepower. These data are applicable to any vessel
having a similar size engine, not just to commercial vessels.
Unless a ship receives auxiliary steam from dockside facilities, goes immediately into drydock, or is out of
operation after arrival in port, she continues her emissions at dockside. Power must be made available for the ship's
lighting, heating, pumps, refrigeration, ventilation, etc. A few steam ships use auxiliary engines (diesel) to supply
power, but they generally operate one or more main boilers under reduced draft and lowered fuel rates-a very
inefficient process. Motorships (ships powered by internal combustion engines) normally use diesel-powered
generators to furnish auxiliary power.17 Emissions from these diesel-powered generators may also be a source of
underway emissions if they are used away from port. Emissions from auxiliary power systems, in terms of the
1/75 Internal Combustion Engine Sources 3.2.3-1
-------
Table 3.2.3-1. AVERAGE EMISSION FACTORS FOR
COMMERCIAL MOTORSHIPS BY WATERWAY
CLASSIFICATION
EMISSION FACTOR RATING: C
Emissions3
Sulfur oxides'3
(SOxasSO2)
kg/103 liter
lb/103 gal
Carbon monoxide
kg/103 liter
lb/103 gal
Hydrocarbons
kg/103 liter
lb/103 gal
Nitrogen oxides
(NOxasN02)
kg/103 liter
lb/103 gal
Class0
River
3.2
27
12
100
6.0
50
33
280
Great Lakes
3.2
27
13
110
7.0
59
31
260
i
Coastal
3.2
27
13
110
6.0
50
32
270
Expressed as function of fuel consumed (based on emission data from
Reference 2 and population/usage data from References 11 through 16.
bCalculated, not measured. Based on 0.20 percent sulfur content fuel
and density of 0.854 kg/liter (7.12 Ib/gal) from Reference 17.
GVery approximate particulate emission factors from Reference 2 are
470 g/hr (1.04 Ib/hr). The reference does not contain sufficient
information to calculate fuel-based factors.
quantity of fuel consumed, are presented in Table 3.2.3-4. In some instances, fuel quantities used may not be
available, so calculation of emissions based on kilowatt hours (kWh ) produced may be necessary. For operating
loads in excess of zero percent, the mass emissions (ej) in kilograms per hour (pounds per hour) are given by:
el = klef
where: k = a constant that relates fuel consumption to kilowatt hours,
that is, 3.63 x 10'4 1000 liters fuel/kWh
(1)
or
9.59 xlO'5 1000 gal fuel/kWh
1= the load, kW
f = the fuel-specific emission factor from Table 3.2.3-4, kg/103 liter (lb/103 gal)
3.2.3-2
EMISSION FACTORS
1/75
-------
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1/75
Internal Combustion Engine Sources
3.2.3-3
-------
Table 3.2.3-3. DIESEL VESSEL EMISSION FACTORS BY OPERATIMG MODE3
EMISSION FACTOR RATING: C
Horsepower
200
300
500
600
700
900
1550
1580
2500
3600
Mode
Idle
Slow
Cruise
Full
Slow
Cruise
Full
Idle
Cruise
Full
Idle
Slow
Cruise
Idle
Cruise
Idle
2/3
Cruise
Idle
Cruise
Full
Slow
Cruise
Full
Slow
2/3
Cru ise
Full
Slow
2/3
Cru ise
Full
Emissions
Carbon monoxide
lb/103
gal
210.3
145.4
126.3
142.1
59.0
47.3
58.5
282.5
99.7
84.2
171.7
50.8
77.6
293.2
36.0
223.7
62.2
80.9
12.2
3.3
7.0
122.4
44.6
237.7
59.8
126.5
78.3
95.9
148.5
28.1
41.4
62.4
kg/103
liter
25.2
17.4
15.1
17.0
7.1
5.7
7.0
33.8
11.9
10.1
20.6
6.1
9.3
35.1
4.3
26.8
7.5
9.7
1.5
0.4
0.8
14.7
5.3
28.5
7.2
15.2
9.4
11.5
17.8
3.4
5.0
7.5
Hydrocarbons
lb/103
gal
391.2
103.2
170.2
60.0
56.7
51.1
21.0
118.1
44.5
22.8
68.0
16.6
24.1
95.8
8.8
249.1
16.8
17.1
0.64
1.64
16.8
22.6
14.7
16.8
21.3
60.0
25.4
32.8
29.5
kg/103
liter
46.9
12.4
20.4
7.2
6.8
6.1
2.5
14.1
5.3
2.7
8.2
2.0
2.9
11.5
1.1
29.8
2.0
2.1
0.1
0.2
2.0
2.7
1.8
2.0
2.6
7.2
3.0
4.0
3.5
Nitrogen oxides
(NOX asN02)
lb/103
gal
6.4
207.8
422.9
255.0
337.5
389.3
275.1
99.4
338.6
269.2
307.1
251.5
349.2
246.0
452.8
107.5
167.2
360.0
39.9
36.2
37.4
371.3
623.1
472.0
419.6
326.2
391.7
399.6
367.0
358,6
339.6
307.0
kg/103
liter
0.8
25.0
50.7
30.6
40.4
46.7
33.0
11.9
40.6
32.3
36.8
30.1
41.8
29.5
54.2
12.9
20.0
43.1
4.8
4.3
4.5
44.5
74.6
5.7
50.3
39.1
46.9
47.9
44.0
43.0
40.7
36.8
^Reference 2.
Participate and sulfur oxides data are not available.
3.2.3-4
EMISSION FACTORS
1/75
-------
Table 3.2.3-4. AVERAGE EMISSION FACTORS FOR DIESEL-POWERED ELECTRICAL
GENERATORS IN VESSELSa
EMISSION FACTOR RATING: C
Rated
output.b
kW
20
40
200
500
Load,c
% rated
output
0
25
50
75
0
25
50
75
0
25
50
75
0
25
50
75
Emissions
Sulfur oxides
(SOxasSO2)d
lb/103
gal
27
27
27
27
27
27
27
27
27
27
27
27
27
27
27
27
kg/103
liter
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
Carbon
monoxide
lb/103
gal
150
79.7
53.4
28.5
153
89.0
67.6
64.1
134
97.9
62.3
26.7
58.4
53.4
48.1
43.7
kg/103
liter
18.0
9.55
6.40
3.42
18.3
10.7
8.10
7.68
16.1
11.7
7.47
3.20
7.00
6.40
5.76
5.24
Hydro-
carbons
lb/103
gal
263
204
144
84.7
584
370
285
231
135
33.5
17.8
17.5
209
109
81.9
59.1
kg/103
liter
31.5
24.4
17.3
10.2
70.0
44.3
34.2
27.7
16.2
4.01
2.13
2.10
25.0
13.0
9.8
7.08
Nitrogen oxides
(NOxasN02>
lb/103
gal
434
444
477
495
214
219
226
233
142
141
140
137
153
222
293
364
kg/103
liter
52.0
53.2
57.2
59.3
25.6
26.2
27.1
27.9
17.0
16.9
16.8
16.4
18.3
26.6
35.1
43.6
Reference 2.
Maximum rated output of the diesel-powered generator.
cGenerator electrical output (for example, a 20 kW generator at 50 percent load equals 10 kW output).
Calculated, not measured, based on 0.20 percent fuel sulfur content and density of 0.854 kg/liter (7.12 Ib/gal) from Reference 17.
At zero load conditions, mass emission rates (ei) may be approximated in terms of kg/hr (Ib/hr) using the
following relationship:
el - klratedef
where: k = a constant that relates rated output and fuel consumption,
that is, 6.93xlO-5 1000 liters fuel/kW
(2)
or
1000 gal fuel/kW
1.83xlO'5
Crated = the rated output, kW
ef = the fuel-specific emission factor from Table 3.2.3-4, kg/103 liter (lb/103 gal)
Pleasure craft. Many of the engine designs used in inboard pleasure craft are also used either in military vessels
(diesel) or in highway vehicles (gasoline). Out of a total of 700,000 inboard pleasure craft ;egistered in the United
States in 1972, nearly 300,000 were inboard/outdrive. According to sales data, 60 to 70 percent of these
1/75
Internal Combustion Engine Sources
3.2.3-5
-------
inboard/outdrive craft used gasoline-powered automotive engines rated at more ihan 130 horsepower. The
remaining 400,000 pleasure craft used conventional inboard drives that were powered by a variety of powerplants,
both gasoline and diesel. Because emission data are not available for pleasure craft, Coast Guard and automotive
data2'19 are used to characterize emission factors for this class of vessels in Table 3.2.3-5.
Military vessels. Military vessels are powered by a wide variety of both diesel and steam power plants. Many of the
emission data used in this section are the result of emission testing programs conducted by the U.S. Navy and the
U.S. Coast Guard.1"3'5 A separate table containing data on military vessels is not provided here, but the included
tables should be sufficient to calculate approximate military vessel emissions.
TABLE 3.2.3.-5. AVERAGE EMISSION FACTORS FOR INBOARD PLEASURE CRAFT3
EMISSION FACTOR RATING: D
Pollutant
Sulfur oxides0'
(SOX as SC-2)
Carbon monoxide
Hydrocarbons
Nitrogen oxides
(NOX as NO2)
Based on fuel consumption
Diesel engine'3
kg/103
liter
3.2
17
22
41
lb/103
gal
27
140
180
340
Gasoline engine0
kg/103
liter
0.77
149
10.3
15.7
lb/103
gal
6.4
1240
86
131
Based on operating time
Diesel engine"
kg/hr
-
-
Ib/hr
_
_
-
Gasoline engine0
kg/hr
0.008
1.69
0.117
0.179
Ib/hr
0.019
3.73
0.258
0.394
aAverage emission factors are based on the duty cycle developed for large outboards (> 48 kilowatts or > 65 horsepower) from Refer-
ence 7. The above factors take into account the impact of water scrubbing of underwater gasoline engine exhaust, also from Reference
7. All values given are for single engine craft and must be modified for multiple engine vessels.
bBased on tests of diesel engines in Coast Guard vessels. Reference 2.
cBased on tests of automotive engines, Reference 19. Fuel consumption of 11.4 liter/hr (3 gal/hr) assumed The resulting factors are
only rough estimates.
dBased on fuel sulfur content of 0.20 percent for diesel fuel and 0.043 percent for gasoline from References 7 and 17. Calculated using
fuel density of 0.740 kg/liter (6.17 Ib/gal) for gasoline and 0.854 kg/liter (7.12 Ib/gal) for diesel fuel.
References for Section 3.2.3
1. Walter, R. A., A. J. Broderick, J. C. Sturm, and E. C. Klaubert. USCG Pollution Abatement Program: A
Preliminary Study of Vessel and Boat Exhaust Emissions. U.S. Department of Transportation, Transportation
Systems Center. Cambridge, Mass. Prepared for the United States Coast Guard, Washington, D.C. Report No.
DOT-TSC-USCG-72-3. November 1971. 119 p.
3.2.3-6
EMISSION FACTORS
1/75
-------
2. Souza, A. F. A Study of Emissions from Coast Guard Cutters. Final Report. Scott Research Laboratories, Inc.
Plumsteadville, Pa. Prepared for the Department of Transportation, Transportation Systems Center,
Cambridge, Mass., under Contract No. DOT-TSC-429. February 1973.
3. Wallace, B. L. Evaluation of Developed Methodology for Shipboard Steam Generator Systems. Department of
the Navy. Naval Ship Research and Development Center. Materials Department. Annapolis, Md. Report No.
28-463. March 1973. 18 p.
4. Waldron, A. L. Sampling of Emission Products from Ships' Boiler Stacks. Department of the Navy. Naval Ship
Research and Development Center. Annapolis, Md. Report No. 28-169. April 1972. 7 p.
5. Foernsler, R. 0. Naval Ship Systems Air Contamination Control and Environmental Data Base Programs;
Progress Report. Department of the Navy. Naval Ship Research and Development Center. Annapolis, Md.
Report No. 28-443. February 1973. 9 p.
6. The Boating Business 1972. The Boating Industry Magazine. Chicago, 111. 1973.
7. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Final Report Part 2. Outboard Motors. Southwest Research Institute. San
Antonio, Tex. Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under
Contract No. EHS 70-108. January 1973. 57 p.
8. Hurst, J. W. 1974 Chrysler Gasoline Marine Engines. Chrysler Corporation. Detroit, Mich.
9. Mercruiser Sterndrives/ Inboards 73. Mercury Marine, Division of the Brunswick Corporation. Fond du Lac,
Wise. 1972.
10. Boating 1972. Marex. Chicago, Illinois, and the National Association of Engine and Boat Manufacturers.
Greenwich, Conn. 1972. 8 p.
11. Transportation Lines on the Great Lakes System 1970. Transportation Series 3. Corps of Engineers, United
States Army, Waterborne Commerce Statistics Center. New Orleans, La. 1970. 26 p.
12. Transportation Lines on the Mississippi and the Gulf Intracoastal Waterway 1970. Transportation Series 4.
Corps of Engineers, United States Army, Waterborne Commerce Statistics Center. New Orleans, La. 1970. 232
P-
13. Transportation Lines on the Atlantic, Gulf and Pacific Coasts 1970. Transportation Series 5. Corps of
Engineers. United States Army. Waterborne Commerce Statistics Center. New Orleans, La. 1970. 201 p.
14. Schueneman, J. J. Some Aspects of Marine Air Pollution Problems on the Great Lakes. J. Air Pol. Control
Assoc. 14:23-29, September 1964.
15. 1971 Inland Waterborne Commerce Statistics. The American Waterways Operations, Inc. Washington, D.C.
October 1972. 38 p.
16. Horsepower on the Inland Waterways. List No. 23. The Waterways Journal. St. Louis, Mo. 1972. 2 p.
17. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Part 1. Locomotive Diesel Engines and Marine Counterparts. Southwest
Research Institute. San Antonio, Tex. Prepared for the Environmental Protection Agency, Research Triangle
Park, N.C., under Contract No. EHS 70-108. October 1972. 39 p.
18. Pearson, J. R. Ships as Sources of Emissions. Puget Sound Air Pollution Control Agency. Seattle, Wash.
(Presented at the Annual Meeting of the Pacific Northwest International Section of the Air Pollution Control
Association. Portland, Ore. November 1969.)
19. Study of Emissions from Light-Duty Vehicles in Six Cities. Automotive Environmental Systems, Inc. San
Bernardino, Calif. Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under
Contract No. 68-04-0042. June 1971.
1/75 Internal Combustion Engine Sources 3.2.3-7
-------
-------
3.2.4 Outboard-Powered Vessels
by David S. Kircher
3.2.4.1 General — Most of the approximately 7 million outboard motors in use in the United States are 2-stroke
engines with an average available horsepower of about 25. Because of the predominately leisure-time use of
outboard motors, emissions related to their operation occur primarily during nonworking hours, in rural areas,
and during the three summer months. Nearly 40 percent of the outboards are operated in the states of New York,
Texas, Florida, Michigan, California, and Minnesota. This distribution results in the concentration of a large
portion of total nationwide outboard emissions in these states.1
3.2.4.2 Emissions — Because the vast majority of outboards have underwater exhaust, emission measurement is
very difficult. The values presented in Table 3.2.4-1 are the approximate atmospheric emissions from outboards.
These data are based on tests of four outboard motors ranging from 4 to 65 horsepower.1 The emission results
from these motors are a composite based on the nationwide breakdown of outboards by horsepower. Emission
factors are presented two ways in this section: in terms of fuel use and in terms of work output (horsepower
hour). The selection of the factor used depends on the source inventory data available. Work output factors are
used when the number of outboards in use is available. Fuel-specific emission factors are used when fuel
consumption data are obtainable.
Table 3.2.4-1. AVERAGE EMISSION FACTORS FOR OUTBOARD MOTORS3
EMISSION FACTOR RATING: B
Pollutant13
Sulfur oxidesd
(SOxasSO2)
Carbon monoxide
Hydrocarbons6
Nitrogen oxides
(NOxasN02)
Based on fuel consumption
lb/103gal
6.4
3300
1100
6.6
kg/103 liter
0.77
400
130
0.79
Based on work output0
g/hphr
0.49
250
85
0.50
g/metric hphr
0.49
250
85
0.50
a Reference 1. Data in this table are emissions to the atmosphere, A portion of the exhaust remains behind in
the water.
Paniculate emission factors are not available because of the problems involved with measurement from an
underwater exhaust system but are considered negligible.
c Horsepower hours are calculated by multiplying the average power produced during the hours of usage by
the population of outboards in a given area. In the absence of data specific to a given geographic area, the
hphr value can be estimated using average nationwide values from Reference 1. Reference 1 reports the
average power produced (not the available power) as 9 1 hp and the average annual usage per engine as 50
hours. Thus, hphr = (number of outboards) (9.1 hp) (50 hours/outboard-year) Metric hphr = 0.9863 hphr.
Based on fuel sulfur content of 0.043 percent from Reference 2 and on a density of 6.17 Ib/gal
e Includes exhaust hydrocarbons only. No crankcase emissions occur because the majority of outboards are
2-stroke engines that use crankcase induction. Evaporative emissions are limited by the widespread use of
unvented tanks.
4/73
Internal Combustion Engine Sources
3.2.4-1
-------
References for sections 3.2.4
1. Hai£, C.T. and K.J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Part II, Outboard Motors. Final Report. Southwest Research Institute. San
Antonio, Texas. Prepared for the Environmental Protection Agency. Research Triangle Park, N.C., under
Contract Number EHS 70-108. January 1973.
2. Hare. C.T. and K.J. Springer. Study of Exhaust Emissions from Uncontrolled Vehicles and Related Equipment
Using Internal Combustion Engines. Emission Factors and Impact Estimates for Light-Duty Air-Cooled Utility
Engines and Motorcycles. Southwest Research Institute. San Antonio, Texas. Prepared for the Environmental
Protection Agency, Research Triangle Park, N.C., under Contract Number EHS 70-108. January 1972.
3.2.4-2 EMISSION FACTORS 4/73
-------
3.2.5 Small, General Utility Engines Revised by Charles C. Masser
3.2.5.1 General-This category of engines comprises small 2-stroke and 4-stroke, air-cooled, gasoline-powered
motors. Examples of the uses of these engines are: lawnmowers. small electric generators, compressors, pumps,
minibikes, snowthrowers, and garden tractors. This category does not include motorcycles, outboard motors, chain
saws, and snowmobiles, which are either included in other parts of this chapter or are not included because of the
lack of emission data.
Approximately 89 percent of the more than 44 million engines of this category in service in the United States
are used in lawn and garden applications.1
3.2.5.2 Emissions—Emissions from these engines are reported in Table 3.2.5-1. For the purpose of emission
estimation, engines in this category have been divided into lawn and garden (2-stroke), lawn and garden (4-stroke),
and miscellaneous (4-stroke). Emission factors are presented in terms of horsepower hours, annual usage, and fuel
consumption.
References for Section 3.2.5
1. Donohue, J. A., G. C. Hardwick, H. K. Newhall, K. S. Sanvordenker, and N. C. Woelffer. Small Engine Exhaust
Emissions and Air Quality in the United States. (Presented at the Automotive Engineering Congress, Society of
Automotive Engineers, Detroit. January 1972.)
2. Hare, C. T. and K. J. Springer. Study of Exhaust Emissions from Uncontrolled Vehicles and Related
Equipment Using Internal Combustion Engines. Part IV, Small Air-Cooled Spark Ignition Utility Engines.
Final Report. Southwest Research Institute. San Antonio, Tex. Prepared for the Environmental Protection
Agency, Research Triangle Park, N.C., under Contract No. EHS 70-108. May 1973.
1/75 Internal Combustion Engine Sources 3.2.5-1
-------
Table 3.2.5-1. EMISSION FACTORS FOR SMALL, GENERAL UTILITY ENGINESa'b
EMISSION FACTOR RATING: B
Engine
2-Stroke, lawn
and garden
g/hphr
g/metric
hphr
g/gal of
fuel
g/unit-
year
4-Stroke, lawn
and garden
g/hphr
g/metric
hphr
g/gal of
fuel
g/unit-
year
4-Stroke
miscellaneous
g/hphr
g/metric
hphr
g/gal of
fuel
g/unit-
year
Sulfur
oxidesc
|SOX as S02)
0.54
0.54
1.80
38
0.37
0.37
2.37
26
0.39
0.39
2.45
30
Paniculate
7.1
7.1
23.6
470
0.44
0.44
2.82
31
0.44
0.44
2.77
34
Carbon
monoxide
486
486
1,618
33,400
279
279
1,790
19,100
250
250
1,571
19,300
Hydrocarbons
Exhaust
214
214
713
14,700
23.2
23.2
149
1,590
15.2
15.2
95.5
1,170
Evaporative
—
-
-
113
-
-
-
113
—
-
-
290
Nitrogen
oxides
(NOX as N02)
1.58
1.58
5.26
108
3.17
3.17
20.3
217
4.97
4.97
31.2
384
Alde-
hydes
(HCHO)
2.04
2.04
6.79
140
0.49
0.49
3.14
34
0.47
0.47
2.95
36
Reference 2.
Values for g/unit-year were calculated assuming an annual usage of 50 hours and a 40 percent load fador. Factors for g/hphr can
be used in instances where annual usages, load factors, and rated horsepower are known. Horsepower hours are the product of the
usage in hours, the load factor, and the rated horsepower.
°Values calculated, not measured, based on the use of 0.043 percent sulfur content fuel.
Values calculated from annual fuel consumption. Evaporative losses from storage and filling operations are not included (see
Chapter 4).
3.2.5-2
EMISSION FACTORS
1/75
-------
3.2.6 Agricultural Equipment
by David S. Kircher
3.2.6.1 General - Farm equipment can be separated into two major categories: wheeled tractors and other farm
machinery. In 1972, the wheeled tractor population on farms consisted of 4.5 million units with an average power
of approximately 34 kilowatts (45 horsepower). Approximately 30 percent of the total population of these
tractors is powered by diesel engines. The average diesel tractor is more powerful than the average gasoline tractor,
that is, 52 kW (70 hp) versus 27 kW (36 hp).v A considerable amount of population and usage data is available
for farm tractors. For example, the Census of Agriculture reports the number of tractors in use for each county in
the U.S.2 Few data are available on the usage and numbers of non-tractor farm equipment, however. Self-propelled
combines, forage harvesters, irrigation pumps, and auxiliary engines on pull-type combines and balers are examples
of non-tractor agricultural uses of internal combustion engines. Table 3.2.6-1 presents data on this equipment for
the U.S.
3.2.6.2 Emissions — Emission factors for wheeled tractors and other farm machinery are presented in Table
3.2.6-2. Estimating emissions from the time-based emission factors-grams per hour (g/hr) and pounds per hour
(lb/hr)—requires an average usage value in hours. An approximate figure of 550 hours per year may be used or, on
the basis of power, the relationship, usage in hours = 450 + 5.24 (kW - 37.2) or usage in hours = 450 + 3.89 (hp -
50) may be employed.^
The best emissions estimates result from the use of "brake specific" emission factors (g/kWh or g/hphr).
Emissions are the product of the brake specific emission factor, the usage in hours, the power available, and the
load factor (power used divided by power available). Emissions are also reported in terms of fuel consumed.
Table 3.2.6-1. SERVICE CHARACTERISTICS OF FARM EQUIPMENT
(OTHER THAN TRACTORS)3
Machine
Combine, self-
propelled
Combine, pull
type
Corn pickers
and picker-
shellers
Pick-up balers
Forage
harvesters
Miscellaneous
Units in
service, x1Q3
434
289
687
655
295
1205
Typical
size
4.3m
(14ft)
2.4m
(8ft)
2 -row
5400 kg/hr
(6 ton/hr)
3.7 m
(12ft) or
3-row
-
Typical power
kW
82
19
_b
30
104
22
hp
110
25
40
140
30
Percent
gasoline
50
100
100
0
50
Percent
diesel
50
0
0
100
50
Reference 1.
Unpowered.
1/75
Internal Combustion Engine Sources
3.2.6-1
-------
Table 3.2.6-2. EMISSION FACTORS FOR WHEELED FARM TRACTORS AND
NON-TRACTOR AGRICULTURAL EQUIPMENT3
EMISSION FACTOR RATING: C
Pollutant
Carbon monoxide
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Exhaust
hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Crankcase
hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Evaporative
hydrocarbons"
g/unit-year
Ib/unit-year
Nitrogen oxides
(NOxasN02)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Aldehydes
(RCHOasHCHO)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Sulfur oxides0
(SOxasS02)
g/hr
Ib/hr
Diesel farm
tractor
161
0.355
4.48
3.34
14.3
119
77.8
0.172
2.28
1.70
7.28
60.7
—
_
-
—
—
-
-
—
452
0.996
12.6
9.39
40.2
335
16.3
0.036
0.456
0.340
1.45
12.1
42.2
0.093
Gasoline farm
tractor
3,380
7.46
192
143
391
3,260
128
0.282
7.36
5.49
15.0
125
26.0
0.057
1.47
1.10
3.01
25.1
15,600
34.4
157
0.346
8.88
6.62
18.1
151
7.07
0.016
0.402
0.300
0.821
6.84
5.56
0.012
Diesel farm
equipment
(non-tractor)
95.2
0.210
5.47
4.08
16.7
139
38.6
0.085
2.25
1.68
6.85
57.1
._
—
-
„
__
—
-
-
210
0.463
12.11
9.03
36.8
307
7.23
0.016
0.402
0.30
1.22
10.2
21.7
0.048
Gasoline farm
equipment
(non-tractor)
4,360
9.62
292
218
492
4,100
143
0.315
9.63
7.18
16.2
135
28.6
0.063
1.93
1.44
3.25
27.1
1,600
3.53
105
0.231
7.03
5.24
11.8
98.5
4.76
0.010
0.295
0.220
0.497
4.14
6.34
0.014
3.2.6-2
EMISSION FACTORS
1/75
-------
Table 3.2.6-2. (continued). EMISSION FACTORS FOR WHEELED FARM TRACTORS AND
NON-TRACTOR AGRICULTURAL EQUIPMENT3
EMISSION FACTOR RATING: C
Pollutant
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Paniculate
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Diesel farm
tractor
1.17
0.874
3.74
31.2
61.8
0.136
1.72
1.28
5.48
45.7
Gasoline farm
tractor
0.312
0.233
0.637
5.31
8.33
0.018
0.471
0.361
0.960
8.00
Diesel farm
equipment
(non-tractor)
1.23
0.916
3.73
31.1
34.9
0.077
2.02
1.51
6.16
51.3
Gasoline farm
equipment
(non-tractor)
0.377
0.281
0.634
5.28
7.94
0.017
0.489
0.365
0.823
6.86
Reference 1.
Crankcase and evaporative emissions from diesel engines are considered negligible.
Not measured. Calculated from fuel sulfur content of 0.043 percent and 0.22 percent for gasoline-powered and diesel-
powered equipment, respectively.
References for Section 3.2.6
1. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Final Report. Part 5: Heavy-Duty Farm, Construction and Industrial Engines.
Southwest Research Institute, San Antonio, Tex. Prepared for Environmental Protection Agency, Research
Triangle Park, N.C., under Contract No. EHS 70-108. August 1973. 97 p.
2. County Farm Reports. U.S. Census of Agriculture. U.S. Department of Agriculture. Washington, D.C.
1/75
Internal Combustion Engine Sources
3.2.6-3
-------
-------
3.2.7 Heavy-Duty Construction Equipment by David S. Kircher
3.2.7.1 General — Because few sales, population, or usage data are available for construction equipment, a number
of assumptions were necessary in formulating the emission factors presented in this section.1 The useful life of
construction equipment is fairly short because of the frequent and severe usage it must endure. The annual usage of
the various categories of equipment considered here ranges from 740 hours (wheeled tractors and rollers) to 2000
hours (scrapers and off-highway trucks). This high level of use results in average vehicle lifetimes of only 6 to 16
years. The equipment categories in this section include: tracklaying tractors, tracklaying shovel loaders, motor
graders, scrapers, off-highway trucks, wheeled loaders, wheeled tractors, rollers, wheeled dozers, and miscellaneous
machines. The latter category contains a vast array of less numerous mobile and semi-mobile machines used in
construction, such as, belt loaders, cranes, pumps, mixers, and generators. With the exception of rollers, the
majority of the equipment within each category is diesel-powered.
3.2.7.2 Emissions - Emission factors for heavy-duty construction equipment are reported in Table 3.2.7-1 for
diesel engines and in Table 3.2.7-2 for gasoline engines. The factors are reported in three different forms-on the
basis of running time, fuel consumed, and power consumed. In order to estimate emissions from time-based
emission factors, annual equipment usage in hours must be estimated. The following estimates of use for the
equipment listed in the tables should permit reasonable emission calculations.
Category
Tracklaying tractors
Tracklaying shovel loaders
Motor graders
Scrapers
Off-highway trucks
Wheeled loaders
Wheeled tractors
Rollers
Wheeled dozers
Miscellaneous
Annual operation, hours/year
1050
1100
830
2000
2000
1140
740
740
2000
1000
The best method for calculating emissions, however, is on the basis of "brake specific" emission factors (g/kWh
or g/hphr). Emissions are calculated by taking the product of the brake specific emission factor, the usage in hours,
the power available (that is, rated power), and the load factor (the power actually used divided by the power
available).
References for Section 3.2.7
1. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines - Final Report. Part 5: Heavy-Duty Farm, Construction, and Industrial Engines.
Southwest Research Institute, San Antonio, Tex. Prepared for Environmental Protection Agency, Research
Triangle Park, N.C., under Contract No. EHS 70-108. October 1973. 105 p.
2. Hare, C. T. Letter to C. C. Masser of Environmental Protection Agency, Research Triangle Park, N.C.,
concerning fuel-based emission rates for farm, construction, and industrial engines. San Antonio, Tex. January
14, 1974. 4 p.
1/75 Internal Combustion Engine Sources 3.2.7-1
-------
Table 3.2.7-1. EMISSION FACTORS FOR HEAVY-DUTY, DIESEL-POWERED CONSTRUCTION
EQUIPMENT3
EMISSION FACTOR RATING: C
Pollutant
Carbon monoxide
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Exhaust hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Nitrogen oxides
(NOxaslMO2)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Aldehydes
(RCHOasHCHO)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Sulfur oxides
(SO as S02)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Particulate
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Tracklaying
tractor
175.
0.386
3.21
2.39
10.5
87.5
50.1
0.110
0.919
0.685
3.01
25.1
665.
1.47
12.2
9.08
39.8
332.
12.4
0.027
0.228
0.170
0.745
6.22
62.3
0.137
1.14
0.851
3.73
31.1
50.7
0.112
0.928
0.692
3.03
25.3
Wheeled
tractor
973.
2.15
5.90
4.40
19.3
161.
67.2
0.148
1.86
1.39
6.10
50.9
451.
0.994
12.5
9.35
41.0
342.
13.5
0.030
0.378
0.282
1.23
10.3
40.9
0.090
1.14
0.851
3.73
31.1
61.5
0.136
1.70
1.27
5.57
46.5
Wheeled
dozer
335.
0.739
2.45
1.83
7.90
65.9
106.
0.234
0.772
0.576
2.48
20.7
2290.
5.05
16.8
12.5
53.9
450.
29.5
0.065
0.215
0.160
0.690
5.76
158.
0.348
1.16
0.867
3.74
31.2
75.
0.165
0.551
0.411
1.77
14.8
Scraper
660.
1.46
3.81
2.84
11.8
98.3
284.
0.626
1.64
1.22
5.06
42.2
2820.
6.22
16.2
12.1
50.2
419.
65.
0.143
0.375
0.280
1.16
9.69
210.
0.463
1.21
0.901
3.74
31.2
184.
0.406
1.06
0.789
3.27
27.3
Motor
grader
97.7
0.215
2.94
2.19
. 9.35
78.0
24.7
0.054
0.656
0.489
2.09
17.4
478.
1.05
14.1
10.5
44.8
374.
5.54
0.012
0.162
0.121
0.517
4.31
39.0
0.086
1.17
0.874
3.73
31.1
27.7
0.061
0.838
0.625
2.66
22.2
References 1 and 2.
3.2.7-2
EMISSION FACTORS
1/75
-------
Table 3.2.7-1 (continued). EMISSION FACTORS FOR HEAVY-DUTY, DIESEL-POWERED
CONSTRUCTION EQUIPMENTS
EMISSION FACTOR RATING: C
Pollutant
Carbon monoxide
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Exhaust hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Nitrogen oxides
(NOX as N02>
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Aldehydes
(RCHOasHCHO)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Sulfur oxides
(SOxasSO2>
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Particulate
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Wheeled
loader
251.
0.553
3.51
2.62
11.4
95.4
84.7
0.187
1.19
0.888
3.87
32.3
1090.
2.40
15.0
11.2
48.9
408.
18.8
0.041
0.264
0.197
0.859
7.17
82.5
0.182
1.15
0.857
3.74
31.2
77.9
0.172
1.08
0.805
3.51
29.3
Tracklaying
loader
72.5
0.160
2.41
1.80
7.90
65.9
14.5
0.032
0.485
0.362
1.58
13.2
265.
0.584
8.80
6.56
28.8
240.
4.00
0.009
0.134
0.100
0.439
3.66
34.4
0.076
1.14
0.853
3.74
31.2
26.4
0.058
0.878
0.655
2.88
24.0
Off-
Highway
truck
610.
1.34
3.51
2.62
11.0
92.2
198.
0.437
1.14
0.853
3.60
30.0
3460.
7.63
20.0
14.9
62.8
524.
51.0
0.112
0.295
0.220
0.928
7.74
206.
0.454
1.19
0.887
3.74
31.2
116.
0.256
0.673
0.502
2.12
17.7
Roller
83.5
0.184
4.89
3.65
13.7
114.
24.7
0.054
1.05
0.781
2.91
24.3
474.
1.04
21.1
15.7
58.5
488.
7.43
0.016
0.263
0.196
0.731
6.10
30.5
0.067
1.34
1.00
3.73
31.1
22.7
0.050
1.04
0.778
2.90
24.2
Miscel-
laneous
188.
0.414
3.78
2.82
11.3
94.2
71.4
0.157
1.39
1.04
4.16
34.7
1030.
2.27
19.8
14.8
59.2
494.
13.9
0.031
0.272
0.203
0.813
6.78
64.7
0.143
1.25
0.932
3.73
31.1
63.2
0.139
1.21
0.902
3.61
30.1
References 1 and 2.
1/75
Internal Combustion Engine Sources
3.2.7-3
-------
Table 3.2.7-2. EMISSION FACTORS FOR HEAVY-DUTY GASOLINE-POWERED
CONSTRUCTION EQUIPMENT®
EMISSION FACTOR RATING: C
Pollutant
Carbon monoxide
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Exhaust hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Evaporative
hydrocarbons'3
g/hr
Ib/hr
Crankcase
hydrocarbons'3
g/hr
Ib/hr
Nitrogen oxides
(NOX as N02)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Aldehydes
(RCHOasHCHO)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Sulfur oxides
(SOX as S02)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Wheeled
tractor
4320.
9.52
190.
142.
389.
3250.
164.
0.362
7.16
5.34
14.6
122.
30.9
0.0681
32.6
0.0719
195.
0.430
8.54
6.37
17.5
146.
7.97
0.0176
0.341
0.254
0.697
5.82
7.03
0.0155
0.304
0.227
0.623
5.20
Motor
grader
5490.
12.1
251.
187.
469.
3910.
186.
0.410
8.48
6.32
15.8
132.
30.0
0.0661
37.1
0.0818
145.
0.320
6.57
4.90
12.2
102.
8.80
0.0194
0.386
0.288
0.721
6.02
7.59
0.0167
0.341
0.254
0.636
5.31
Wheeled
loader
7060.
15.6
219.
163.
435.
3630.
241.
0.531
7.46
5.56
14.9
124.
29.7
0.0655
48.2
0.106
235.
0.518
7.27
5.42
14.5
121.
9.65
0.0213
0.298
0.222
0.593
4.95
10.6
0.0234
0.319
0.238
0.636
5.31
Rolfer
6080.
13.4
271.
202.
460.
3840.
277.
0.611
12.40
9.25
21.1
176.
28.2
0.0622
55.5
0.122
164.
0.362
7.08
528
12.0
100.
7.57
0.0167
0.343
0.256
0.582
4.86
8.38
0.0185
0.373
0.278
0.633
5.28
Miscel-
laneous
7720.
17.0
266.
198.
475.
3960.
254.
0.560
8.70
6.49
15.6
130.
25.4
0.0560
50.7
0.112
187.
0.412
6.42
4.79
11.5
95.8
9.00
0.0198
0.298
0.222
0.532
4.44
10.6
0.0234
0.354
0.264
0.633
5.28
3.2.7-4
EMISSION FACTORS
1/75
-------
Table 3.2.7-2. (continued). EMISSION FACTORS FOR HEAVY-DUTY GASOLINE-POWERED
CONSTRUCTION EQUIPMENT3
EMISSION FACTOR RATING: C
Pollutant
Particulate
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Wheeled
tractor
10.9
0.0240
0.484
0.361
0.991
8.27
Motor
grader
9.40
0.0207
0.440
0.328
0.822
6.86
Wheeled
loader
13.5
0.0298
0.421
0.314
0.839
7.00
Roller
11.8
0.0260
0.527
0.393
0.895
7.47
Miscel-
laneous
11.7
0.0258
0.406
0.303
0.726
6.06
a,
References 1 and 2.
""Evaporative and crankcase hydrocarbons based on operating time only (Reference 1).
1/75
Internal Combustion Engine Sources
3.2.7-5
-------
-------
3.2.8 Snowmobiles by Charles C. Masser
3.2,8.1 General — In order to develop emission factors for snowmobiles, mass emission rates must be known, and
operating cycles representative of usage in the field must be either known or assumed. Extending the applicability
of data from tests of a few vehicles to the total snowmobile population requires additional information on the
composition of the vehicle population by engine size and type. In addition, data on annual usage and total machine
population are necessary when the effect of this source on national emission levels is estimated.
An accurate determination of the number of snowmobiles in use is quite easily obtained because most states
require registration of the vehicles. The most notable features of these registration data are that almost 1.5 million
sleds are operated in the United States, that more than 70 percent of the snowmobiles are registered in just four
states (Michigan, Minnesota, Wisconsin, and New York), and that only about 12 percent of all snowmobiles are
found in areas outside the northeast and northern midwest.
3.2.8.2 Emissions — Operating data on snowmobiles are somewhat limited, but enough are available so that an
attempt can be made to construct a representative operating cycle. The required end products of this effort are
time-based weighting factors for the speed/load conditions at which the test engines were operated; use of these
factors will permit computation of "cycle composite" mass emissions, power consumption, fuel consumption, and
specific pollutant emissions.
Emission factors for snowmobiles were obtained through an EPA-contracted study ^ in which a variety of
snowmobile engines were tested to obtain exhaust emissions data. These emissions data along with annual usage
data were used by the contractor to estimate emission factors and the nationwide emission impact of this pollutant
source.
To arrive at average emission factors for snowmobiles, a leasonable estimate of average engine size was
necessary. Weighting the size of the engine to the degree to which each engine is assumed to be representative of
the total population of engines in service resulted in an estimated average displacement of 362 cubic centimeters
(cm3).
The speed/load conditions at which the test engines were operated represented, as closely as possible, the
normal operation of snowmobiles in the field. Calculations using the fuel consumption data obtained during the
tests and the previously approximated average displacement of 362 cm3 resulted in an estimated average fuel
consumption of 0.94 gal/hr.
To compute snowmobile emission factors on a gram per unit year basis, it is necessary to know not only the
emission factors but also the annual operating time. Estimates of this usage are discussed in Reference 1. On a
national basis, however, average snowmobile usage can be assumed to be 60 hours per year. Emission factors for
snowmobiles are presented in Table 3.2.8-1.
References for Section 3.2.8
1. Hare, C. T. and K. J. Springer. Study of Exhaust Emissions from Uncontrolled Vehicles and Related
Equipment Using Internal Combustion Engines. Final Report. Part 7: Snowmobiles. Southwest Research
Institute, San Antonio, Tex. Prepared for Environmental Protection Agency, Research Triangle Park, N.C.,
under Contract No. EHS 70-108. April 1974.
1/75 Internal Combustion Engine Sources 3.2.8-1
-------
Table 3.2.8-1. EMISSION FACTORS FOR
SNOWMOBILES
EMISSION FACTOR RATING: B
Pollutant
Carbon monoxide
Hydrocarbons
Nitrogen oxides
Sulfur oxides0
Solid particulate
Aldehydes (RCHO)
Emissions
g/unit-yeara
58,700
37,800
600
51
1,670
552
g/gaib
1,040.
670.
10.6
0.90
29.7
9.8
g/literb
275.
177.
2.8
0.24
7.85
2.6
g/hrb
978.
630.
10.0
0.85
27.9
£1.2
3 "%
Based on 60 hours of operation per year and 362 cm displacement.
Based on 362 cm displacement and average fuel consumption of 0,94 gal/hr.
°Based on sulfur content of 0.043 percent by weight.
3.2.8-2
EMISSION FACTORS
1/75
-------
3.3 OFF-HIGHWAY, STATIONARY SOURCES by David S. Kircher and
Charles C. Masser
In general, engines included in this category are internal combustion engines used in applications similar to those
associated with external combustion sources (see Chapter 1). The major engines within this category are gas
turbines and large, heavy-duty, general utility reciprocating engines. Emission data currently available for these
engines are limited to gas turbines and natural-gas-fired, heavy-duty, general utility engines. Most stationary
internal combustion engines are used to generate electric power, to pump gas or other fluids, or to compress air for
pneumatic machinery.
3.3.1 Stationary Gas Turbines for Electric Utility Power Plants
3.3.1.1 General - Stationary gas turbines find application in electric power generators, in gas pipeline pump and
compressor drives, and in various process industries. The majority of these engines are used in electrical generation
for continuous, peaking, or standby power.l The primary fuels used are natural gas and No. 2 (distillate) fuel oil,
although residual oil is used in a few applications.
3.3.1.2 Emissions - Data on gas turbines were gathered and summarized under an EPA contract.2 The contractor
found that several investigators had reported data on emissions from gas turbines used in electrical generation but
that little agreement existed among the investigators regarding the terms in which the emissions were expressed.
The efforts represented by this section include acquisition of the data and their conversion to uniform terms.
Because many sets of measurements reported by the contractor were not complete, this conversion often involved
assumptions on engine air flow or fuel flow rates (based on manufacturers' data). Another shortcoming of the
available information was that relatively few data were obtained at loads below maximum rated (or base) load.
Available data on the population and usage of gas turbines in electric utility power plants are fairly extensive,
and information from the various sources appears to be in substantial agreement. The source providing the most
complete information is the Federal Power Commission, which requires major utilities (electric revenues of $1
million or more) to submit operating and financial data on an annual basis. Sawyer and Farmer^ employed these
data to develop statistics on the use of gas turbines for electric generation in 1971. Although their report involved
only the major, publicly owned utilities (not the private or investor-owned companies), the statistics do appear to
include about 87 percent of the gas turbine power used for electric generation in 1971.
Of the 253 generating stations listed by Sawyer and Farmer, 137 have more than one turbine-generator unit.
From the available data, it is not possible to know how many hours each turbine was operated during 1971 for
these multiple-turbine plants. The remaining 116 (single-turbine) units, however, were operated an average of 1196
hours during 1971 (or 13.7 percent of the time), and their average load factor (percent of rated load) during
operation was 86.8 percent. This information alone is not adequate for determining a representative operating
pattern for electric utility turbines, but it should help prevent serious errors.
Using 1196 hours of operation per year and 250 starts per year as normal, the resulting average operating day is
about 4.8 hours long. One hour of no-load time per day would represent about 21 percent of operating time, which
is considered somewhat excessive. For economy considerations, turbines are not run at off-design conditions any
longer than necessary, so time spent at intermediate power points is probably minimal. The bulk of turbine
operation must be at base or peak load to achieve the high load factor already mentioned.
If it is assumed that time spent at off-design conditions includes 15 percent at zero load and 2 percent each at
25 percent, 50 percent, and 75 percent load, then the percentages of operating time at rated load (100 percent)
and peak load (assumed to be 125 percent of rated) can be calculated to produce an 86.8 percent load factor.
These percentages turn out to be 19 percent at peak load and 60 percent at rated load; the postulated cycle based
on this line of reasoning is summarized in Table 3.3.1-1.
1/75 Internal Combustion Engine Sources 3.3.1-1
-------
Table 3.3.1-1. TYPICAL OPERATING CYCLE FOR ELECTRIC
UTILITY TURBINES
Condition,
% of rated
power
0
25
50
75
100 (base)
125 (peak)
Percent operating
time spent
at condition
15
2
2
2
60
19
Time at condition
based on 4.8-hr day
hours
0.72
0.10
0.10
0.10
2.88
0.91
4.81
minutes
43
6
6
6
173
55
289
Contribution to load
factor at condition
0.00x0.15 = 0.0
0.25 x 0.02 = 0.005
0.50x0.02 = 0.010
0.75x0.02 = 0.015
1.0 x 0.60 = 0.60
1.25x0.19 = 0.238
Load factor = 0.868
The operating cycle in Table 3.3.1-1 is used to compute emission factors, although it is only an estimate of actual
operating patterns.
Table 3.3.1-2. COMPOSITE EMISSION FACTORS FOR 1971
POPULATION OF ELECTRIC UTILITY TURBINES
EMISSION FACTOR RATING: B
Time basis
Entire population
Ib/hr rated load3
kg/hr rated load
Gas-fired only
Ib/hr rated load
kg/hr rated load
Oil-fired only
Ib/hr rated load
kg/hr rated load
Fuel basis
Gas- fired only
Ib/106ft3gas
kg/106m3 gas
Oil-fired only
lb/103galoil
kg/103 liter oil
Nitrogen
oxides
8.84
4.01
7.81
3.54
9.60
4.35
413.
6615.
67.8
8.13
Hydro-
carbons
0.79
0.36
0.79
0.36
0.79
0.36
42.
673.
5.57
0.668
Carbon
Monoxide
2.18
0.99
2.18
0.99
2.18
0.99
115.
1842.
15.4
1.85
Panic-
ulate
0.52
0.24
0.27
0.12
0.71
0.32
14.
224.
5.0
0.60
Sulfur
oxides
0.33
0.15
0.098
0.044
0.50
0.23
5.2
83.
3.5
0.42
Rated load expressed in megawatts.
Table 3.3.1-2 is the resultant composite emission factors based on the operating cycle of Table 3.3.1-1 and the
1971 population of electric utility turbines".
3.3.1-2
EMISSION FACTORS
1/75
-------
Different values for time at base and peak loads are obtained by changing the total time at lower loads (0
through 75 percent) or by changing the distribution of time spent at lower loads. The cycle given in Table 3.3.1-1
seems reasonable, however, considering the fixed load factor and the economies of turbine operation. Note that the
cycle determines only the importance of each load condition in computing composite emission factors for each
type of turbine, not overall operating hours.
The top portion of Table 3.3.1-2 gives separate factors for gas-fired and oil-fired units, and the bottom portion
gives fuel-based factors that can be used to estimate emission rates when overall fuel consumption data are
available. Fuel-based emission factors on a mode basis would also be useful but present fuel consumption data are
not adequate for this purpose.
References for Section 3.3.1
1. O'Keefe, W. and R. G. Schwieger. Prime Movers. Power. 115(\ 1): 522-531. November 1971.
2. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Final Report. Part 6: Gas Turbine Electric Utility Power Plants. Southwest
Research Institute, San Antonio, Tex. Prepared for Environmental Protection Agency, Research Triangle Park,
N.C., under Contract No. EHS 70-108, February 1974.
3. Sawyer, V. W. and R. C. Farmer. Gas Turbines in U.S. Electric Utilities. Gas Turbine International. January —
April 1973.
1/75 Internal Combustion Engine Sources 3.3.1-3
-------
-------
3.3.2 Heavy-Duty, Natural-Gas-Fired Pipeline Compressor Engines by Susan Sercer
Alan Burgess
Tom Lahre
3.3.2.1 General1 - Engines in the natural gas industry are used primarily to power compressors used for pipeline
transportation, field gathering (collecting gas from wells), underground storage, and gas processing plant
applications. Pipeline engines are concentrated in the major gas producing states (such as those along the Gulf
Coast) and along the major gas pipelines. Both reciprocating engines and gas turbines are utilized, but the trend
has been toward use of large gas turbines. Gas turbines emit considerably fewer pollutants than do reciprocating
engines; however, reciprocating engines are generally more efficient in their use of fuel.
3.3.2.2 Emissions and Controls1 '2 - The primary pollutant of concern is NOX, which readily forms in the high
temperature, pressure, and excess air environment found in natural-gas-fired compressor engines. Lesser amounts
of carbon monoxide and hydrocarbons are emitted, although for each unit of natural gas burned, compressor
engines (particularly reciprocating engines) emit significantly more of these pollutants than do external
combustion boilers. Sulfur oxides emissions are proportional to the sulfur content of the fuel and will usually be
quite low because of the negligible sulfur content of most pipeline gas.
The major variables affecting NOX emissions from compressor engines include the air fuel ratio, engine load
(defined as the ratio of the operating horsepower divided by the rated horsepower), intake (manifold) air
temperature, and absolute humidity. In general, NOX emissions increase with increasing load and intake air
temperature and decrease with increasing absolute humidity and air fuel ratio. (The latter already being, in most
compressor engines, on the "lean" side of that air fuel ratio at which maximum NOX formation occurs.)
Quantitative estimates of the effects of these variables are presented in Reference 2.
Because NOX is the primary pollutant of significance emitted from pipeline compressor engines, control
measures to date have been directed mainly at limiting NOX emissions. For gas turbines, the most effective
method of controlling NOX emissions is the injection of water into the combustion chamber. Nitrogen oxides
reductions as high as 80 percent can be achieved by this method. Moreover, water injection results in only
nominal reductions in overall turbine efficiency. Steam injection can also be employed, but the resulting NOX
reductions may not be as great as with water injection, and it has the added disadvantage that a supply of steam
must be readily available. Exhaust gas recirculation, wherein a portion of the exhaust gases is recirculated back
into the intake manifold, may result in NOX reductions of up to 50 percent. This technique, however, may not be
practical in many cases because the recirculated gases must be cooled to prevent engine malfunction. Other
combustion modifications, designed to reduce the temperature and/or residence time of the combustion gases,
can also be effective in reducing NOX emissions by 10 to 40 percent in specific gas turbine units.
For reciprocating gas-fired engines, the most effective NOX control measures are those that change the air-fuel
ratio. Thus, changes in engine torque, speed, intake air temperature, etc., that in turn increase the air-fuel ratio,
may all result in lower NOX emissions. Exhaust gas recirculation may also be effective in lowering NOX emissions
although, as with turbines, there are practical limits because of the large quantities of exhaust gas that must be
cooled. Available data suggest that other NOX control measures, including water and steam injection, have only
limited application to reciprocating gas-fired engines.
Emission factors for natural-gas-fired pipeline compressor engines are presented in Table 3.3.2-1.
4/76 Internal Combustion Engine Sources 3.3.2-1
-------
Table 3.3.2-1. EMISSION FACTORS FOR HEAVY-DUTY, NATURAL-
GAS-FIRED PIPELINE COMPRESSOR ENGINES3
EMISSION FACTOR RATING: A
Reciprocating engines
lb/103hp-hr
g/hp-hr
g/kW-hr
lb/106scff
kg/106Nm3f
Gas turbines
lb/103hp-hr
g/hp-hr
g/kW-hr
Ib/106scf9
kg/106Nm39
Nitrogen oxides
-------
3.3.3 Gasoline and Diesel Industrial Engines
by David S. Kircher
3.3.3-1 General - This engine category covers a wide variety of industrial applications of both gasoline and diesel
internal combustion power plants, such as fork lift trucks, mobile refrigeration units, generators, pumps, and
portable well-drilling equipment. The rated power of these engines covers a rather substantial range—from less than
15 kW to 186 kW (20 to 250 hp) for gasoline engines and from 34 kW to 447 kW (45 to 600 hp) for diesel engines.
Understandably, substantial differences in both annual usage (hours per year) and engine duty cycles also exist. It
was necessary, therefore, to make reasonable assumptions concerning usage in order to formulate emission
factors.1
3.3.3-2 Emissions - Once reasonable usage and duty cycles for this category were ascertained, emission values
from each of the test engines l were aggregated (on the basis of nationwide engine population statistics) to arrive at
the factors presented in Table 3.3.3-1. Because of their aggregate nature, data contained in this table must be
applied to a population of industrial engines rather than to an individual power plant.
The best method for calculating emissions is on the basis of "brake specific" emission factors (g/kWh or
Ib/hphr). Emissions are calculated by taking the product of the brake specific emission factor, the usage in hours
(that is, hours per year or hours per day), the power available (rated power), and the load factor (the power
actually used divided by the power available).
Table 3.3.3-1. EMISSION FACTORS FOR GASOLINE-
AND DIESEL-POWERED INDUSTRIAL EQUIPMENT
EMISSION FACTOR RATING: C
Pollutant3
Carbon monoxide
9/br
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Exhaust hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Evaporative hydrocarbons
g/hr
Ib/hr
Crankcase hydrocarbons
g/hr
Ib/hr
Engine category
Gasoline
5700.
12.6
267.
199.
472.
3940.
191.
0.421
8.95
6.68
15.8
132.
62.0
0.137
38.3
0.084
Diesel
197.
0.434
4.06
3.03
12.2
102.
72.8
0.160
1.50
1.12
4.49
37.5
-
_
1/75
Internal Combustion Engine Sources
3.3.3-1
-------
Table 3.3.3-1. (continued). EMISSION FACTORS FOR GASOLINE-
AND DIESEL-POWERED INDUSTRIAL EQUIPMENT
EMISSION FACTOR RATING: C
Pollutant3
Nitrogen oxides
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Aldehydes
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Sulfur oxides
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Particulate
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Engine category"
Gasoline
148.
0.326
6.92
5.16
12.2
102.
6.33
0.014
0.30
0.22
0.522
4.36
7.67
0.017
0.359
0.268
0.636
5.31
9.33
0.021
0.439
0.327
0.775
6.47
Diesel
910.
2.01
18.8
14.0
56.2
469.
13.7
0.030
0.28
0.21
0.84
7.04
60.5
0.133
1.25
0.931
3.74
31.2
65.0
0.143
1.34
1.00
4.01
33.5
References 1 and 2.
As discussed in the text, the engines used to determine the results in this
table cover a wide range of uses and power. The listed values do not,
however, necessarily apply to some very large stationary diesel engines.
References for Section 3.3.3
1. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Final Report. Part 5: Heavy-Duty Farm, Construction, and Industrial Engines.
Southwest Research Institute. San Antonio, Texas. Prepared for Environmental Protection Agency, Research
Triangle Park, N.C., under Contract No. EHS 70-108. October 1973. 105 p.
2. Hare, C. T. Letter to C. C. Masser of the Environmental Protection Agency concerning fuel-based emission
rates for farm, construction, and industrial engines. San Antonio, Tex. January 14, 1974.
3.3.3-2
EMISSION FACTORS
1/75
-------
4. EVAPORATION LOSS SOURCES
Evaporation losses include the organic solvents emitted from dry-cleaning plants and surface-
coating operations as well as the volatile matter in petroleum products. This chapter presents the
hydrocarbon emissions from these sources, including liquid petroleum storage and marketing. Where
possible, the effect of controls to reduce the emissions of organic compounds has been shown.
4.1 DRY CLEANING by Susan Sercer
4.1.1 General1'2
Dry cleaning involves the cleaning of fabrics with non-aqueous organic solvents. The dry cleaning
process requires three steps: (1) washing the fabric in solvent, (2) spinning to extract excess solvent, and
(3) drying by tumbling in a hot airstream.
Two general types of cleaning fluids are used in the industry: petroleum solvents and synthetic sol-
vents. Petroleum solvents, such as Stoddard or 140-F, are inexpensive, combustible hydrocarbon
mixtures similar to kerosene. Operations using petroleum solvents are known as petroleum plants.
Synthetic solvents are nonflammable but more expensive halogenated hydrocarbons. Perchloro-
ethylene and trichlorotrifluoroethane are the two synthetic dry cleaning solvents presently in
use. Operations using these synthetic solvents are called "perc" plants and fluorocarbon plants,
respectively.
There are two basic types of dry cleaning machines: transfer and dry-to-dry. Transfer machines ac-
complish washing and drying in separate machines. Usually the washer extracts excess solvent from the
clothes before they are transferred to the dryer, however, some older petroleum plants have separate
extractors for this purpose. Dry-to-dry machines are single units that perform all of the washing,
extraction, and drying operations. All petroleum solvent machines are the transfer type, but synthetic
solvent plants can be either type.
The dry cleaning industry can be divided into three sectors: coin-operated facilities, commercial
operations, and industrial cleaners. Coin-operated facilities are usually part of a laundry and supply
"self-service" type dry cleaning for consumers. Only synthetic solvents are used in coin-operated dry
cleaning machines. Such machines are small, with a capacity of 8 to 25 Ib (3.6 to 11.5 kg) of clothing.
Commercial operations, such as small neighborhood or franchise dry cleaning shops, clean soiled
apparel for the consumer. Generally, perchloroethylene and petroleum solvents are used in commer-
cial operations. A typical "perc" plant operates a 30 to 60 Ib (14 to 27 kg) capacity washer/extractor and
an equivalent size reclaiming dryer.
Industrial cleaners are larger dry cleaning plants which supply rental service of uniforms, mats,
mops, etc., to businesses or industries. Although petroleum solvents are used extensively, perchloro-
ethylene is used by approximately 50% of the industrial dry cleaning establishments. A typical large in-
dustrial cleaner has a 500 Ib (230 kg) capacity washer/ extractor and three to six 100 Ib (38 kg) capacity
dryers.
A typical perc plant is shown in Figure 4.1-1. Although one solvent tank may be used, the typical
perc plant uses two tanks for washing. One tank contains pure solvent; the other tank contains
"charged" solvent — used solvent to which small amounts of detergent have been added to aid in clean-
ing. Generally, clothes are cleaned in charged solvent and rinsed in pure solvent. A water bath may also
be used.
4/77 Evaporative Loss Sources 4.1-1
-------
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4.1-2
EMISSION FACTORS
4/77
-------
After the clothes have been washed, the used solvent is filtered, and part of the filtered solvent is re-
turned to the charged solvent tank for washing the next load. The remaining solvent is then distilled to
remove oils, fats, greases, etc., and returned to the pure solvent tank. The resulting distillation'bot-
toms are typically stored on the premises until disposed of. The filter cake and collected solids (muck)
are usually removed from the filter once a day. Before disposal, the muck may be "cooked" to recover
additional solvent. Still and muck cooker vapors are vented to a condenser and separator where more
solvent is reclaimed. In many perc plants, the condenser off-gases are vented to a carbon adsorption
unit for additional solvent recovery.
After washing, the clothes are transferred to the dryer where they are tumbled in a heated air-
stream. Exhaust gases from the dryer, along with a small amount of exhaust gases from the washer/ex-
tractor, are vented to a water-cooled condenser and water separator. Recovered solvent is returned to
the pure solvent storage tank. In 30-50 percent of the perc plants, the condenser off-gases are vented to
a carbon adsorption unit for additional solvent recovery. To reclaim this solvent, the unit must be
periodically desorbed with steam—typically at the end of each day. Desorbed solvent and water are
condensed and separated; recovered solvent is returned to the pure solvent tank.
A petroleum plant would differ from Figure 4.1-1 chiefly in that there would be no recovery of sol-
vent from the washer and dryer and no muck cooker. A fluorocarbon plant would differ in that a non-
vented refrigeration system would be used in place of a carbon adsorption unit. Another difference
would be that a typical fluorocarbon plant would use a cartridge filter which is drained and disposed
of after several hundred cycles.
Emissions and Controls1"2'3
The solvent material itself is the primary emission of concern from dry cleaning operations. Sol-
vent is given off by the washer, dryer, solvent still, muck cooker, still residue and filter muck storage
areas, as well as leaky pipes, flanges, and pumps.
Petroleum plants have generally not employed solvent recovery because of the low cost of petro-
leum solvents and the ^ *e -lazards associated with collecting vapors. Some emission control, however,
can be obtained by mt Plaining all equipment in good condition (e.g., preventing lint accumulation,
preventing solvent leakage, etc.) and by using good operating practices (e.g., not overloading machin-
ery). Both carbon adsorption and incineration appear to be technically feasible controls for petroleum
plants, but costs are high.
Solvent recovery is necessary in perc plants due to the higher cost of perchloroethylene. As shown in
Figure 4.1-1, recovery is effected on the washer, dryer, still, and muck cooker through the use of con-
densers, water/solvent separators, and carbon adsorption units. Periodically (typically once a day), sol-
vent collected in the carbon adsorption unit is desorbed with steam, condensed, separated from the
condensed water, and returned to the pure solvent storage tank. Residual solvent emitted from treat-
ed distillation bottoms and muck is not recovered. As in petroleum plants, good emission control can
be obtained by good housekeeping practices (maintaining all equipment in good condition and using
good operating practices).
All fluorocarbon machines are of the dry-to-dry variety to conserve solvent vapor, and all are closed
systems with built-in solvent recovery. High emissions can occur, however, as a result of poor mainte-
nance and operation of equipment. Refrigeration systems are installed on newer machines to recover
solvent from the washer/dryer exhaust gases.
Emission factors for dry cleaning operations are presented in Table 4.1-1.
4/77 Evaporative Loss Sources 4.1-3
-------
Table 4.1-1. SOLVENT LOSS EMISSION FACTORS FOR DRY CLEANING OPERATIONS
EMISSION FACTOR RATING: B
Solvent type
(Process used)
Petroleum
(transfer process)
Perchloroethylene
(transfer process)
Trichlorotrifluoroethane
(dry-to-dry process)
Source
washer/dryerf
filter disposal
uncooked (drained)
centrifuged
still residue disposal
miscellaneous0
washer/dryer/still/muck cooker
filter disposal
uncooked muck
cooked muck
cartridge filter
still residue disposal
miscellaneous0
washer/dryer/still6
cartridge filter disposal
still residue disposal
miscellaneous0
_ 1
Emission rate3
Typical systems
lb/100lb (kg/1 00 kg)
18
5
2
3
3d
14
1.3
1.1
1.6
1.5
0
1
0.5
1 -3
Well-controlled system
lb/100lb (kg/100 kg)
2b
0.5-1
0.5- 1
1
0.3b
0.5- 1.3
0.5-1.1
0.5-1.6
1
0
1
0.5
1 -3
aUnits are in terms of weight of solvent per weight of clothes cleaned (capacity x loads). Emissions may be estimated on an alternative
basis by determining the amount of solvent consumed. Assuming that all solvent input to dry cleaning operations is eventually
evaporated to the atmosphere, an emission factor of 2000 Ib/ton of solvent consumed can be applied. All emission factors are based
on References 1, 2 and 3.
''Emissions from the washer, dryer, still, and muck cooker are collectively passed through a carbon adsorber.
cMiscellaneous sources include fugitive emissions from flanges, pumps, pipes, storage tanks, fixed losses I for example, opening and
closing the dryer), etc.
^Uncontrolled emissions from the washer, dryer, still, and muck cooker average about 8 lb/100 Ib (8 kg/100 kg). Roughly 15% of
the solvent emitted comes from the washer, 75% from the dryer, and 5% from both the still and the muck cooker.
eEmission factors are based on the typical refrigeration system installed in fluorocarbon plants.
f Different materials in the wash retain varying amounts of solvent (synthetic: 10 kg/100 kg, cotton: 20 kg/100 kg, leather: 40 kg/
100kg).
References for Section 4.1
1. Study to Support New Source Performance Standards for the Dry Cleaning Industry, EPA Con-
tract 68-02-1412, Task Order No. 4, prepared by TRW Inc., Vienna, Virginia, May 7, 1976.
Kleeberg, Charles, EPA, Office of Air Quality Planning and Standards.
2. Standard Support and Environmental Impact Statement for the Dry Cleaning Industry. Dur-
ham, North Carolina. June 28, 1976.
3. Control of Volatile Organic Emissions from Dry Cleaning Operations (Draft Document), Dur-
ham, North Carolina. April 15, 1977.
4.1-4
EMISSION FACTORS
4/77
-------
4.2 SURFACE COATING
4.2.1 Process Description1 >2
Surface-coating operations primarily involve the application of paint, varnish, lacquer, or paint primer for
decorative or protective purposes. This is accomplished by brushing, rolling, spraying, flow coating, and dipping.
Some of the industries involved in surface-coating operations are automobile assemblies, aircraft companies,
container manufacturers, furniture manufacturers, appliance manufacturers, job enamelers, automobile re-
painters, and plastic products manufacturers.
4.2.2 Emissions and Controls3
Emissions of hydrocarbons occur in surface-coating operations because of the evaporation of the paint
vehicles, thinners, and solvents used to facilitate the application of the coatings. The major factor affecting these
emissions is the amount of volatile matter contained in the coating. The volatile portion of most common surface
coatings averages approximately 50 percent, and most, if not all, of this is emitted during the application and
drying of the coating. The compounds released include aliphatic and aromatic hydrocarbons, alcohols, ketones,
esters, alkyl and aryl hydrocarbon solvents, and mineral spirits. Table 4.2-1 presents emission factors for
surface-coating operations.
Control of the gaseous emissions can be accomplished by the use of adsorbers (activated carbon) or
afterburners. The collection efficiency of activated carbon has been reported at 90 percent or greater. Water
curtains or filler pads have little or no effect on escaping solvent vapors; they are widely used, however, to stop
paint particulate emissions.
Table 4.2-1. GASEOUS HYDROCARBON EMISSION
FACTORS FOR SURFACE-COATING APPLICATIONS3
EMISSION FACTOR RATING: B
Type of coating
Paint
Varnish and shellac
Lacquer
Enamel
Primer (zinc chromate)
Emissions'3
Ib/ton
1120
1000
1540
840
1320
kg/MT
560
500
770
420
660
3 Reference 1.
"Reported as undefined hydrocarbons, usually organic solvents, both
aryl and alkyl. Paints weigh 10 to 15 pounds per gallon (1.2 to 1.9
kilograms per liter); varnishes weigh about 7 pounds per gallon
(0.84 kilogram per liter).
2/72 Evaporation Loss Sources 4.2-1
-------
References for Section 4.2
1. Weiss, S.F. Surface Coating Operations. In: Air Pollution Engineering Manual, Danielson, J.A. (ed.). U.S.
DHEW, PHS, National Center for Air Pollution Control. Cincinnati, Ohio. Publication Number 999-AP-40.
p.387-390.
2. Control Techniques for Hydrocarbon and Organic Gases From Stationary Sources. U.S. DHEW, PHS, EHS,
National Air Pollution Control Administration. Washington, D.C. Publication Number AP-68. October 1969.
Chapter 7.6.
3. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
4.2-2 EMISSION FACTORS 2/72
-------
4.3 STORAGE OF PETROLEUM LIQUIDS1 by Charles C. Master
Fundamentally, the petroleum industry consists of three operations: (1) petroleum production and
transportation, (2) petroleum refining, and (3) transportation and marketing of finished petroleum
products. All three operations require some type of storage for petroleum liquids. Storage tanks for
both crude and finished products can be sources of evaporative emissions. Figure 4.3-1 presents a
schematic of the petroleum industry and its points of emissions from storage operations.
4.3.1 Process Description
Four basic tank designs are used for petroleum storage vessels: fixed roof, floating roof (open type
and covered type), variable vapor space, and pressure (low and high).
4.3.1.1 Fixed Roof Tanks2 - The minimum accepted standard for storage of volatile liquids is the
fixed roof tank (Figure 4.3-2). It is usually the least expensive tank design to construct. Fixed roof tanks
basically consist of a cylindrical steel shell topped by a coned roof having a minimum slope of 3/4
inch in 12 inches. Fixed roof tanks are generally equipped with a pressure/vacuum vent designed to
contain minor vapor volume changes. For large fixed roof tanks, the recommended maximum operat-
ing pressure/vacuum is +0.03 psig/-0.03 psig (+2.1 g/cm2/-2.1 g/cm2).
4.3.1.2 Floating Roof Tanks3 - Floating roof tanks reduce evaporative storage losses by minimizing va-
por spaces. The tank consists of a welded or riveted cylindrical steel wall, equipped with a deck or roof
which is free to float on the surface of the stored liquid. The roof then rises and falls according to the
depth of stored liquid. To ensure that the liquid surface is completely covered, the roof is equipped
with a sliding seal which fits against the tank wall. Sliding seals are also provided at support columns
and at all other points where tank appurtenances pass through the floating roof.
Until recent years, the most commonly used floating roof tank was the conventional open-type
tank. The open-type floating roof tank exposes the roof deck to the weather; provisions must be made
for rain water drainage, snow removal, and sliding seal dirt protection. Floating roof decks are of three
general types: pan, pontoon, and double deck. The pan-type roof consists of a flat metal plate with a
vertical rim and sufficient stiffening braces to maintain rigidity (Figure 4.3-3). The single metal plate
roof in contact with the liquid readily conducts solar heat, resulting in higher vaporization losses than
other floating roof decks. The roof is equipped with automatic vents for pressure and vacuum release.
The pontoon roof is a pan-type floating roof with pontoon sections added to the top of the deck around
the rim. The pontoons are arranged to provide floating stability under heavy loads of water and snow.
Evaporation losses due to solar heating are about the same as for pan-type roofs. Pressure/vacuum
vents are required on pontoon roof tanks. The double deck roof is similar to a pan-type floating roof,
but consists of a hollow double deck covering the entire surface of the roof (Figure 4.3-4). The double
deck adds rigidity, and the dead air space between the upper and lower deck provides significant insu-
lation from solar heating. Pressure/vacuum vents are also required.
The covered-type floating roof tank is essentially a fixed-roof tank with a floating roof deck inside
the tank (Figure 4.3-5). The American Petroleum Institute has designated the term "covered floating"
roof to describe a fixed roof tank with an internal steel pan-type floating roof. The term "internal float-
ing cover" has been chosen by the API to describe internal covers constructed of materials other than
steel. Floating roofs and covers can be installed inside existing fixed roof tanks. The fixed roof protects
the floating roof from the weather, and no provision is necessary for rain or snow removal, or for seal
4/77 Evaporation Loss Sources 4.3-1
-------
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4/77
-------
, PRESSURE-VACUUM
VENT
GAUGE HATCH,
MANHOLE
Figure 4.3-2. Fixed roof storage tank.
, ROOF SEAL (METALLIC SHOW
WIATHER 1HIELD-
NOZZLE
Figure 4.3-3. Pan-type floating roof storage tank (metallic seals).
ROOF SEAL
• (NON-METALUC)
WEATHER SHKLD-
NOZZLE
Figure 4.3-4. Double deck floating roof storage tank (non-metallic seals).
4/77
Evaporation Loss Sources
4.3-3
-------
AIR SCOOPS.
NOZZLE
Figure 4.3-5. Covered floating roof storage tank.
protection. Antirotational guides must be provided to maintain roof alignment, and the space be-
tween the fixed and floating roofs must be vented to prevent the possible formation of a flammable
mixture.
4.3.1.3 Variable Vapor Space Tanks4 - Variable vapor space tanks are equipped with expandable
vapor reservoirs to accommodate vapor volume fluctuations attributable to temperature and baro-
metric pressure changes. Although variable vapor space tanks are sometimes used independently, they
are normally connected to the vapor spaces of one or more fixed roof tanks. The two most common
types of variable vapor space tanks are lifter roof tanks and flexible diaphragm tanks.
Lifter roof tanks have a telescoping roof that fits loosely around the outside of the main tank wall.
The space between the roof and the wall is closed by either a wet seal, which consists of a trough filled
with liquid, or a dry seal, which employs a flexible coated fabric in place of the trough (Figure 4.3-6).
-PRESSURE-VACUUM
VtKT
NOZZLE
Figure 4.3-6. Lifter roof storage tank (wet seal).
Flexible diaphragm tanks utilize flexible membranes to provide the expandable volume. They may
be separate gasholder type units, or integral units mounted atop fixed roof tanks (Figure 4.3-7)..
4.3-4
EMISSION FACTORS
4/77
-------
PRESSURE
VACUUM VENTS
NOZZLE
Figure 4.3-7. Flexible diaphragm tank (integral unit).
4.3.1.4 Pressure Tanks5 - Pressure tanks are designed to withstand relatively large pressure variations
without incurring a loss. They are generally used for storage of high volatility stocks, and they are
constructed in many sizes and shapes, depending on the operating range. The noded spheroid and
noded hemispheroid shapes are generally used as low-pressure tanks (17 to 30 psia or 12 to 21 mg/m2),
while the horizontal cylinder and spheroid shapes are generally used as high-pressure tanks (up to 265
psia or 186 mg/m2).
4.3.2 Emissions and Controls
There are six sources of emissions from petroleum liquids in storage: fixed roof breathing losses,
fixed roof working losses, floating roof standing storage losses, floating roof withdrawal losses, vari-
able vapor space filling losses, and pressure tank losses.6
Fixed roof breathing losses consist of vapor expelled from a tank because of the thermal expansion
of existing vapors, vapor expansion caused by barometric pressure changes, and/or an increase in the
amount of vapor due to added vaporization in the absence of a liquid-level change.
Fixed roof working losses consist of vapor expelled from a tank as a result of filling and emptying
operations. Filling loss is the result of vapor displacement by the input of liquid. Emptying loss is the
expulsion of vapors subsequent to product withdrawal, and is attributable to vapor growth as the new-
ly inhaled air is saturated with hydrocarbons.
Floating roof standing storage losses result from causes other than breathing or changes in liquid
level. The largest potential source of this loss is attributable to an improper fit of the seal and shoe to
the shell, which exposes some liquid surface to the atmosphere. A small amount of vapor may escape
between the flexible membrane seal and the roof.
Floating roof withdrawal losses result from evaporation of stock which wets the tank wall as the
roof descends during emptying operations. This loss is small in comparison to other types of losses.
4/77
Evaporation Loss Sources
4.3-5
-------
Variable vapor space filling losses result when vapor is displaced by the liquid input during filling
operations. Since the variable vapor space tank has an expandable vapor storage capacity, this loss is
not as large as the filling loss associated with fixed roof tanks. Loss o f vapor occurs only when the vapor
storage capacity of the tank is exceeded.
Pressure tank losses occur when the pressure inside the tank exceeds the design pressure of the
tank, which results in relief vent opening. This happens only when the tank is filled improperly, or
when abnormal vapor expansion occurs. These are not regularly occurring events, and pressure tanks
are not a significant source of loss under normal operating conditions.
The total amount of evaporation loss from storage tanks depends upon the rate of loss and the per-
iod of time involved. Factors affecting the rate of loss include:
1. True vapor pressure of the liquid stored.
2. Temperature changes in the tank.
3. Height of the vapor space (tank outage).
4. Tank diameter.
5. Schedule of tank filling and emptying.
6. Mechanical condition of tank and seals.
7. Type of tank and type of paint applied to outer surface.
The American Petroleum Institute has developed empirical formulae, based on field testing, that cor-
relate evaporative losses with the above factors and other specific storage factors.
4.3.2.1 Fixed Roof Tanks2*7 - Fixed roof breathing losses can be estimated from:
LB = 2.21 x 10-4 M [—L_]°-68 D1.73 UPSI ^0.50 F c K (1)
where: Lg = Fixed roof breathing loss (Ib/day).
M = Molecular weight of vapor in storage tank (Ib/lb mole), (see Table 4.3-1).
P = True vapor pressure at bulk liquid conditions (psia); see Figures 4.3-8, 4.3-9,
or Table 4.3-1.
D = Tank diameter (ft).
H = Average vapor space height, including roof volume correction ('ft); see note (1).
AT = Average ambient temperature change from day to night (°F).
Fp = Paint factor (dimensionless); see Table 4.3-2.
C = Adjustment factor for small diameter tanks (dimensionless); see Figure 4.3-10.
KC = Crude oil factor (dimensionless); see note (2).
Note: (1) The vapor space in a cone roof is equivalent in volume to a cylinder which has the
same base diameter as the cone and is one-third the height of the cone.
(2) Kc = (0.65) for crude oil, Kc = (1.0) for gasoline and all other liquids.
API reports that calculated breathing loss from Equation (1) may deviate in the order of + 10 percent
from actual breathing loss.
4.3-6 EMISSION FACTORS 4/77
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Evaporation Loss Sources
4.3-7
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10 PER CENT EVAPORATED »
OEG F AT 15 PER CENT MINUS OEG F AT 5 PER CENT
10
IN THE ABSENCE OF DISTILLATION DATA THE
ING AVERAGE VALUE OF S MAY BE USED :
MOTOR GASOLINE
AVIATION GASOLINE
LIGHT NAPHTHA C9-I4L3 RVP)
NAPHTHA (2-8 LS RVP)
FOLLOW-
3
2
3.5
2.5
,.J
_
-
-
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Figure 4.3-8. Vapor pressures of gasolines and finished petroleum products.
4.3-8
EMISSION FACTORS
4/77
-------
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4/77
Figure 4.3-9. Vapor pressures of crude oil.
Evaporation Loss Sources
4.3-9
-------
Table 4.3-2. PAINT FACTORS FOR FIXED ROOF TANKS3
Tank color
Roof
White
Aluminum (specular)
White
Aluminum (specular)
White
Aluminum (diffuse)
White
Light gray
Medium gray
Shell
White
White
Aluminum (specular)
Aluminum (specular)
Aluminum (diffuse)
Aluminum (diffuse)
Gray
Light gray
Medium gray
Paint factors (Fp)
Paint condition
Good
1.00
1.04
1.16
1.20
1.30
1.39
1.30
1.33
1.40
Poor
1.15
1.18
1.24
1.29
1.38
1.46
1.38
1.44a
1.58a
aEstimated from the ratios of the seven preceding paint factors.
ADJUSTMENT FACTOR C
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A
t
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/
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P"
MM"
10 20
TANK DIAMETER IN FEET
Figure 4.3-10. Adjustment factor (C) for
small diameter tanks.
30
Fixed roof working losses can be estimated from:
LW = 2.40 x ID'2 MPKNKC
(2)
4.3-10
EMISSION FACTORS
4/77
-------
where: L
W
M
P
K
Kc
Fixed roof working loss (lb/103 gal throughput).
Molecular weight of vapor in storage tank (Ib/lb mole), see Table 4.3-1.
True vapor pressure at bulk liquid conditions (psia); see Figures 4.3-8, 4.3-9,
or Table 4.3-1.
Turnover factor (dimensionless); see Figure 4.3-11.
Crude oil factor (dimensionless); see note.
Note: Kc = (0.84) for crude oil, K = (1.0) for gasoline and all other liquids.
1.0
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NOTE: FOR 38 TURNOVERS PER
YEAR OR LESS. KN -1.0
100
200
300
400
TURNOVERS PER YEAR
ANNUAL THROUGHPUT
TANK CAPACITY
Figure 4.3-11. Turnover factor (K|\|) for fixed roof tanks.
The fixed roof working loss (L\^)is the sum of the loading and unloading loss. API reports that special
tank operating conditions may result in actual losses which are significantly greater or lower than the
estimates provided by Equation (2).
The API recommends the use of these storage loss equations only for cases in which the stored petro-
leum liquids exhibit vapor pressures in the same range as gasolines. However, in the absence of any cor-
relation developed specifically for naphthas, kerosenes, and fuel oils, it is recommended that these
storage loss equations also be used for the storage of these heavier fuels.
The method most commonly used to control emissions from fixed roof tanks is a vapor recovery sys-
tem that collects emissions from the storage vessels and converts them to liquid product. To recover va-
por, one or a combination of four methods may be used: vapor/liquid absorption, vapor compression,
vapor cooling, and vapor/solid adsorption. Overall control efficiencies of vapor recovery systems vary
4/77
Evaporation Loss Sources
4.3-11
-------
from 90 to 95 percent, depending on the method used, the design of the unit, the composition of vapors
recovered, and the mechanical condition of the system.
Emissions from fixed roof tanks can also be controlled by the addition of an internal floating cover
or covered floating roof to the existing fixed roof tank. API reports that this can result in an average
loss reduction of 90 percent of the total evaporation loss sustained from a fixed roof tank.8
Evaporative emissions can be minimized by reducing tank heat input with water sprays, mechani-
cal cooling, underground storage, tank insulation, and optimum scheduling of tank turnovers.
4.3.2.2 Floating Roof Tanks3'7 - Floating roof standing storage losses can be estimated from:
LS = 9.21 x ID"3 M^-j^J0'7 Dl-5vwO-7KtKsKpKc (3)
where: LC = Floating roof standing storage loss (Ib/day).
M = Molecular weight of vapor in storage tank (Ib/lb mole); see Table 4.3-1.
P = True vapor pressure at bulk liquid conditions (psia); see Figures 4.3-8, 4.3-9,
or Table 4.3-1.
D = Tank diameter (ft); see note (1).
Vw = Average wind velocity (mi/hr); see note (2).
Kt = Tank type factor (dimensionless); see Table 4.3-3.
Kg = Seal factor (dimensionless); see Table 4.3-3.
K = Paint factor (dimensionless); see Table 4.3-3.
K = Crude oil factor (dimensionless); see note (3).
Note: (1) For D > 150, use D/Tso" instead of D.1 5
(2) API correlation was derived for minimum wind velocity of 4 mph. If Vw
<. 4 mph, use Vw = 4mph.
(3) Kc = (0.84) for crude oil, Kc = (1.0) for all other liquids.
API reports that standing storage losses from gasoline and crude oil storage calculated from Equa-
tion (3) will not deviate from the actual losses by more than ±25 percent for tanks in good condition un-
der normal operation. However, losses may exceed the calculated amount if the seals are in poor condi-
tion. Although the API recommends the use of these correlations only for petroleum liquids exhibit-
ing vapor pressures in the range of gasoline and crude oils, in the absence of better correlations, these
correlations are also recommended with caution for use with heavier naphthas, kerosenes, and fuel
oils.
4.3-12 EMISSION FACTORS 4/77
-------
Table 4.3-3, TANK, TYPE, SEAL, AND PAINT FACTORS
FOR FLOATING ROOF TANKS2
Tank type
Welded tank with pan or pontoon
roof, single or double seal
Riveted tank with pontoon roof,
double seal
Riveted tank with pontoon roof,
single seal
Riveted tank with pan roof,
double seal
Riveted tank with pan roof,
single seal
Kt
0.045
0.11
0.13
0.13
0.14
Seal type
Tight fitting (typical of modern
metallic and non-metallic seals)
Loose fitting (typical of seals
built prior to 1942)
Paint color of shell and roof
Light gray or aluminum
White
Ks
1.00
1.33
Kp
1.0
0.9
API has developed a correlation based on laboratory data for calculating floating roof withdrawal
loss for gasoline storage.5 Floating roof withdrawal loss for gasoline can be estimated from:
22.4 d Cp
= —
(4)
where:
D
= Floating roof gasoline withdrawal loss (lb/103 gal throughput).
= Density of stored liquid at bulk liquid conditions (Ib/gal); see Table 4.3-1.
= Tank construction factor (dimensionless); see note.
= Tank diameter (ft).
Note: CF = (0.02) for steel tanks, Cp = (1.0) for gunite-lined tanks.
Because Equation (4) was derived from gasoline data, its applicability to other stored liquids is uncer-
tain. No estimate of accuracy of Equation (4) has been given.
API has not presented any correlations that specifically pertain to internal floating covers or cov-
ered floating roofs. Currently, API recommends the use of Equations (3) and (4) with a wind speed of 4
mph for calculating the losses from internal floating covers and covered floating roofs.
Evaporative emissions from floating roof tanks can be minimized by reducing tank heat input.
4.3.2.3 Variable Vapor Space Systems 4«7- Variable vapor space system filling losses can be estimated
from:
-, M P
Lv = (2.40 x ID'2) ~-
- (0.25 V2 N)]
(5)
4/77
Evaporation Loss Sources
4.3-13
-------
where: Ly = Variable vapor space filling loss (lb/103 gal throughput).
M = Molecular weight of vapo.r in storage tank (Ib/lb mole); see Table 4.3-1.
P = True vapor pressure at bulk liquid conditions (psia); see Figures 4.3-8, 4.3-9, or Table
4.3-1.
Vj = Volume of liquid pumped into system: throughput (bbl).
V2 = Volume expansion capacity of system (bbl); see note (1).
N = Number of transfers into system (dimensionless); see note (2).
Note: (1) V is the volume expansion capacity of the variable vapor space achieved by roof-
lifting or diaphragm-flexing.
(2) N is the number of transfers into the system during the time period that corre-
sponds to a throughput of Vr
The accuracy of Equation (5) is not documented; however, API reports that special tank operating
conditions may result in actual losses which are significantly different from the estimates provided by
Equation (5). It should also be noted that, although not developed for use with heavier petroleum
liquids such as kerosenes and fuel oils, Equation (5) is recommended for use with heavier petroleum
liquids in the absence of better data.
Evaporative emissions from variable vapor space tanks are negligible and can be minimized by opti-
mum scheduling of tank turnovers and by reducing tank heat input. Vapor recovery systems can be
used with variable vapor space systems to collect and recover filling losses.
Vapor recovery systems capture hydrocarbon vapors displaced during filling operations and re-
cover the hydrocarbon vapors by the use of refrigeration, absorption, adsorption, and/or compres-
sion. Control efficiencies range from 90 to 98 percent, depending on the nature of the vapors and the
recovery equipment used.
4.3.2.4 Pressure Tanks - Pressure tanks incur vapor losses when excessive internal pressures result in
relief valve venting. In some pressure tanks vapor venting is a design characteristic, and the vented
vapors must be routed to a vapor recovery system. However, for most pressure tanks vapor venting is
not a normal occurrence, and the tanks can be considered closed systems. Fugitive losses are also as-
sociated with pressure tanks and their equipment, but with proper system maintenance they are in-
significant. Correlations do not exist for estimating vapor losses from pressure tanks.
4.3.3 Emission Factors
Equations (1) through (5) can be used to estimate evaporative losses, provided the respective para-
meters are known. For those cases where such parameters are unknown, Table 4.3-4 provides emission
factors for the typical systems and conditions. It should be emphasized that these emission factors are
rough estimates at best for storage of liquids other than gasoline and crude oil, and for storage con-
ditions other than the ones they are based upon. In areas where storage sources contribute a substan-
tial portion of the total evaporative emissions or where they are major factors affecting the air quality,
it is advisable to obtain the necessary parameters and to calculate emission estimates using Equations
(1) through (5).
4.3-14 EMISSION FACTORS 4/77
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4/77
Evaporation Loss Sources
4.3-15
-------
4.3.3.1 Sample Calculation - Breathing losses from a fixed roof storage tank would be calculated as
follows, using Equation (1).
Design basis:
Tank capacity - 100,000 bbl.
Tank diameter - 125 ft.
Tank height - 46 ft.
Average diurnal temperature change - 15° F.
Gasoline RVP - 9 psia.
Gasoline temperature - 70°F.
Specular aluminum painted tank.
Roof slope is 0.1 ft/ft.
Fixed roof tank breathing loss equation:
LB = 2.21 xlO-4M -0'68 Dl-73 H0.51 AT0.50 F? c KC
where: M = Molecular weight of gasoline vapors (see Table 4.3-l)=!66.
P = True vapor of gasoline (see Figure 4.3-8) = 5.6 psia.
D = Tank diameter = 125 ft.
AT = average diurnal temperature change = 15° F.
F = paint factor (see Table 4.3-2) = 1.20.
C = tank diameter adjustment factor (see Figure 4.3-10) = 1.0.
KC = crude oil factor (see note for equation (1)) = 1.0.
H = average vapor space height. For a tank which is filled completely and emptied, the
average liquid level is 1/2 the tank rim height, or 23 ft. The effective cone height is 1/3
of the cone height. The roof slope is 0.1 ft/ft and the tank radius is 62.5 ft. Effective
cone height = (62.5 ft) (0.1 ft/ft) (1/3) = 2.08 ft.
H = average vapor space height = 23 ft + 2 ft = 25 ft.
Therefore:
LB = 2.21 x 10-4 (66) 147-_56' (125)1.73 (25)0-51 (15)0.50 (].2) (1.0) (1.0)
LB = 10681b/day
4.3-16 EMISSION FACTORS 4/77
-------
References for Section 4.3
1. Burklin, C.E. and R.L. Honerkamp. Revision of Evaporative Hydrocarbon Emission Factors,
U.S. Environmental Protection Agency, Research Triangle Park, North Carolina. Report No.
EPA-450/3-76-039. August 15, 1976.
2. American Petroleum Inst., Evaporation Loss Committee. Evaporation Loss From Fixed-Roof
Tanks. Bull. 2518. Washington, D.C. 1962.
3. American Petroleum Inst., Evaporation Loss Committee. Evaporation Loss From Floating-Roof
Tanks. Bull. 2517. Washington, D.C. 1962.
4. American Petroleum Inst., Evaporation Loss Committee. Use of Variable Vapor-Space Systems
To Reduce Evaporation Loss. Bull. 2520. N.Y., N.Y. 1964
5. American Petroleum Inst., Evaporation Loss Committee. Evaporation Loss From Low-Pressure
Tanks. Bull. 2516. Washington, D.C. 1962.
6. American Petroleum Inst., Evaporation Loss Committee. Evaporation Loss In The Petroleum
Industry. Causes and Control. API Bull. 2513. Washington, D.C. 1959.
7. American Petroleum Inst., Div. of Refining, Petrochemical Evaporation Loss From Storage
Tanks. API Bull. 2523. New York. 1969
8. American Petroleum Inst., Evaporation Loss Committee. Use of Internal Floating Covers For
Fixed-Roof Tanks To Reduce Evaporation Loss. Bull. 2519. Washington, D.C. 1962.
9. Barnett, Henry C. et al. Properties Of Aircraft Fuels. Lewis Flight Propulsion Lab., Cleveland,
Ohio. NACA-TN 3276. August 1956.
4/77 Evaporation Loss Sources 4.3-17
-------
-------
4.4 TRANSPORTATION AND MARKETING , _, . r ,.
OF PETROLEUM LIQUIDS1 b? Charles C Masser
4.4.1 Process Description
As Figure 4.4-1 indicates, the transportation and marketing of petroleum liquids involves many
distinct operations, each of which represents a potential source of hydrocarbon evaporation loss.
Crude oil is transported from production operations to the refinery via tankers, barges, tank cars, tank
trucks, and pipelines. In the same manner, refined petroleum products are conveyed to fuel market-
ing terminals and petrochemical industries by tankers, barges, tank cars, tank trucks, and pipelines.
From the fuel marketing terminals, the fuels are delivered via tank trucks to service stations, commer-
cial accounts, and local bulk storage plants. The final destination for gasoline is usually a motor vehicle
gasoline tank. A similar distribution path may also be developed for fuel oils and other petroleum
products,
4.4.2 Emissions and Controls
Evaporative hydrocarbon emissions from the transportation and marketing of petroleum liquids
may be separated into four categories, depending on the storage equipment and mode of transporta-
tion used:
1, Large storage tanks: Breathing, working, and standing storage losses,
2. Marine vessels, tank cars, and tank trucks: Loading, transit, and ballasting losses.
3. Service stations: Bulk fuel drop losses and underground tank breathing losses.
4. Motor vehicle tanks: Refueling losses.
(In addition, evaporative and exhaust emissions are also associated with motor vehicle operation.
These topics are discussed in Chapter 3.)
4.4.2.1 Large Storage Tanks - Losses from storage tanks are thoroughly discussed in Section 4.3.
4.4.2.2 Marine Vessels, Tank Cars, and Tank Trucks - Losses from marine vessels, tank cars, and tank
trucks can be categorized into loading losses, transit losses, and ballasting losses.
Loading losses are the primary source of evaporative hydrocarbon emissions from marine vessel,
tank car, and tank truck operations. Loading losses occur as hydrocarbon vapors residing in empty
cargo tanks are displaced to the atmosphere by the liquid being loaded into the cargo tanks. The
hydrocarbon vapors displaced from the cargo tanks are a composite of (1) hydrocarbon vapors formed
in the empty tank by evaporation of residual product from previous hauls and (2) hydrocarbon vapors
generated in the tank as the new product is being loaded. The quantity of hydrocarbon losses from
loading operations is, therefore, a function of the following parameters:
• Physical and chemical characteristics of the previous cargo.
• Method of unloading the previous cargo.
4/77 Evaporation Loss Sources 4.4-1
-------
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EMISSION FACTORS
4/77
-------
• Operations during the transport of the empty carrier to the loading terminal.
• Method of loading the new cargo.
• Physical and chemical characteristics of the new cargo.
The principal methods of loading cargo carriers are presented in Figures 4.4-2,4.4-3, and 4.4-4. In
the splash loading method, the fill pipe dispensing the cargo is only partially lowered into the cargo
tank. Significant turbulence and vapor-liquid contacting occurs during the splash loading operation,
resulting in high levels of vapor generation and loss. If the turbulence is high enough, liquid droplets
will be entrained in the vented vapors.
FILL PIPE
VAPOR EMISSIONS
-HATCH COVER
CARGO TANK
Figure 4.4-2. Splash loading method.
VAPOR EMISSIONS
FILL PIPE
HATCH COVER
CARGO TANK
Figure 4.4-3. Submerged fill pipe.
A second method of loading is submerged loading. The two types of submerged loading are the
submerged fill pipe method and the bottom loading method. In the submerged fill pipe method, the
fill pipe descends almost to the bottom of the cargo tank. In the bottom loading method, the fill pipe
enters the cargo tank from the bottom. During the major portion of both forms of submerged loading
4/77
Evaporation Loss Sources
4.4-3
-------
VAPOR VENT
TO RECOVERY
OR ATMOSPHERE
HATCH CLOSED
mCARGO TANK
FILL PIPE
Figure 4.4-4. Bottom loading.
methods, the fill pipe opening is positioned below the liquid level. The submerged loading method
significantly reduces liquid turbulence and vapor-liquid contacting, thereby resulting in much lower
hydrocarbon losses than encountered during splash loading methods.
The history of a cargo carrier is just as important a factor in loading losses as the method of loading.
Hydrocarbon emissions are generally lowest from a clean cargo carrier whose cargo tanks are free from
vapors prior to loading. Clean cargo tanks normally result from either carrying a non-volatile liquid
such as heavy fuel oils in the previous haul, or from cleaning or venting the empty cargo tank prior to
loading operations. An additional practice, specific to marine vessels, that has significant impacton
loading losses is ballasting. After unloading a cargo, empty tankers normally fill several cargo tanks
with water to improve the tanker's stability on the return voyage. Upon arrival in port, this I ballast
water is pumped from the cargo tanks before loading the new cargo. The ballasting of cargo tanks
reduces the quantity of vapor returning in the empty tanker, thereby reducing the quantity of vapors
emitted during subsequent tanker loading operations.
In normal dedicated service, a cargo carrier is dedicated to the transport of only one product and
does not clean or vent its tank between trips. An empty cargo tank in normal dedicated service will
retain a low but significant concentration of vapors which were generated by evaporation of residual
product on the tank surfaces. These residual vapors are expelled along with newly generated vapors
during the subsequent loading operation.
Another type of cargo carrier is one in "dedicated balance service." Cargo carriers in dedicated
balance service pick up vapors displaced during unloading operations and transport these vapors in
the empty cargo tanks back to the loading terminal. Figure 4.4-5 shows a tank truck in dedicated vapor
balance service unloading gasoline to an underground service station tank and filling up with dis-
placed gasoline vapors to be returned to the truck loading terminal. The vapors in an empty cargo
carrier in dedicated balance service are normally saturated with hydrocarbons.
4.4-4
EMISSION FACTORS
4/77
-------
MANIFOLD FOR RETURNING VAPORS
VAPOR VENT LINE
TRUCK STORAGE\ I /\ \l\
COMPARTMENTS^ I *
UNDERGROUND
STORAGE TANK
Figure 4.4-5. Tanktruck unloading into an underground service station storage tank.
Tanktruck is practicing "vapor balance" form of vapor control.
Emissions from loading hydrocarbon liquid can be estimated (within 30 percent) using the follow-
ing expression:
LL = 12.46
(i)
where: L^ = Loading loss, lb/103 gal of liquid loaded.
M = Molecular weight of vapors, Ib/lb-mole (see Table 4.3-l)>
P = True vapor pressure of liquid loading, psia (see Figures 4.3-8 and
4.3-9, and Table 4.3-1).
T = Bulk temperature of liquid loaded, °R.
S = A saturation factor (see Table 4.4-1).
4/77 Evaporation Loss Sources
4.4-5
-------
The saturation factor (S) represents the expelled vapor's fractional approach to saturation and
accounts for the variations observed in emission rates from the different unloading and loading
methods. Table 4.4-1 lists suggested saturation factors (S).
Table 4.4-1. S FACTORS FOR CALCULATING PETROLEUM
LOADING LOSSES
Cargo carrier
Tank trucks and tank cars
Marine vessels3
Mode of operation
Submerged loading of a clean
cargo tank
Splash loading of a clean
cargo tank
Submerged loading: normal
dedicated service
Splash loading: normal
dedicated service
Submerged loading: dedicated,
vapor balance service
Splash loading: dedicated,
vapor balance service
Submerged loading: ships
Submerged loading: barges
S factor
0.50
1.45
0.60
1.45
1.00
1.00
0.2
0.5
aTo be used for products other than gasoline; use factors from Table 4.4-2
for marine loading of gasoline.
Recent studies on gasoline loading losses from ships and barges have led to the development of
more accurate emission factors for these specific loading operations. These factors are presented in
Table 4.4-2 and should be used instead of Equation (1) for gasoline loading operations at marine
terminals.2
Ballasting operations are a major source of hydrocarbon emissions associated with unloading
petroleum liquids at marine terminals. It is common practice for large tankers to fill several cargo
tanks with water after unloading their cargo. This water, termed ballast, improves the stability of the
empty tanker on rough seas during the subsequent return voyage. Ballasting emissions occur as hydro-
carbon-laden air in the empty cargo tank is displaced to the atmosphere by ballast water being pumped
into the empty cargo tank. Although ballasting practices vary quite a bit, individual cargo tanks are
ballasted about 80 percent, and the total vessel is ballasted approximately 40 percent of capacity.
Ballasting emissions from gasoline and crude oil tankers are approximately 0.8 and 0.6 lb/103 gal,
respectively, based on total tanker capacity. These estimates are for motor gasolines and medium
volatility crudes (RVP*5 psia).2
An additional emission source associated with marine vessel, tank car, and tank truck operations is
transit losses. During the transportation of petroleum liquids, small quantities of hydrocarbon vapors
are expelled from cargo tanks due to temperature and barometric pressure changes. The most signifi-
cant transit loss is from tanker and barge operations and can be calculated using Equation (2).3
4.4-6
EMISSION FACTORS
4/77
-------
Table 4.4-2. HYDROCARBON EMISSION FACTORS FOR GASOLINE LOADING OPERATIONS
Vessel tank condition
Cleaned and vapor free
lb/103 gal transferred
kg/103 liter transferred
Ballasted
lb/1Q3 gal transferred
kg/103 liter transferred
Uncleaned - dedicated service
lb/!03 gal transferred
kg/IO3 liter transferred
Average cargo tank condition
lb/1Q3 gal transferred
kg/103 liter transferred
Hydrocarbon emission factors
Ships
Range
0 to 2.3
0 to 0.28
0.4 to 3
0.05 to 0.36
0.4 to 4
0.05 to 0.48
a
Average
1.0
0.12
1.6
0.19
2.4
0.29
1.4
0.17
Ocean barges
Range
0 to 3
0 to 0.36
0.5 to 3
0.06 to 0.36
0.5 to 5
0.06 to 0.60
a
Average
1.3
0.16
2.1
0.25
3.3
0.40
a
Barges
Range
a
b
1.4 to 9
0.17 to 1.08
a
Average
1.2
0.14
b
4.0
0.48
4.0
0.48
aThese values are not available.
Barges are not normally ballasted
LT = 0.1 PW
(2)
where: L_, = Transit loss, lb/week-103 gal transported.
P = True vapor pressure of the transported liquid, psia
(see Figures 4.3-8 and 4.3-9, and Table 4.3-1).
W = Density of the condensed vapors, Ib/gal (see Table 4.3-1).
In the absence of specific inputs for Equations (1) and (2), typical evaporative hydrocarbon emis-
sions from loading operations are presented in Table 4.4-3. It should be noted that, although the crude
oil used to calculate the emission values presented in Table 4.4-3 has an RVP of 5, the RVP of crude oils
can range over two orders of magnitude. In areas where loading and transportation sources are major
factors affecting the air quality it is advisable to obtain the necessary parameters and to calculate
emission estimates from Equations (1) and (2).
Control measures for reducing loading emissions include the application of alternate loading
methods producing lower emissions and the application of vapor recovery equipment. Vapor recovery
equipment captures hydrocarbon vapors displaced during loading and ballasting operations and re-
covers the hydrocarbon vapors by the use of refrigeration, absorption, adsorption, and/or compres-
sion. Figure 4.4-6 demonstrates the recovery of gasoline vapors from tank trucks during loading oper-
ation at bulk terminals. Control efficiencies range from 90 to 98 percent depending on the nature of
the vapors and the type of recovery equipment employed.4
4/77
Evaporation Loss Sources
4.4-7
-------
Table 4.4-3. HYDROCARBON EMISSION FACTORS FOR PETROLEUM LIQUID
TRANSPORTATION AND MARKETING SOURCES
Emission source
Tank cars/trucks
Submerged loading-normal service
lb/103 gal transferred
kg/103 liters transferred
Splash loading-normal service
lb/103 gal transferred
kg/103 liters transferred
Submerged loading-balance service
lb/103 gal transferred
kg/103 liters transferred
Splash loading-balance service
lb/103 gal transferred
kg/103 liters transferred
Marine vessels
Loading tankers
lb/103 gal transferred
kg/103 liters transferred
Loading barges
lb/103 gal transferred
kg/103 liters transferred
Tanker ballasting
lb/103 gal cargo capacity
kg/1 03 liters cargo capacity
Transit
lb/week-103 gal transported
kg/week-103 liters transported
Product emission factors
Gasoline
5
0.6
12
1.4
8
1.0
8
1.0
b
b
0.8
0.10
3
0.4
Crude
oil
3
0.4
7
0.8
5
0.6
5
0.6
0.7
0.08
1.7
0.20
0.6
0.07
1
0.1
Jet
naphtha
(JP-4)
1.5
0.18
4
0.5
2.5
0.3
2.5
0.3
0.5
0.06
1.2
0.14
c
0.7
0.08
Jet
kerosene
0.02
0.002
0.04
0.005
a
a
0.005
0.0006
0.013
0.0016
c
0.02
0.002
Distillate
oil
No. 2
0.01
0.001
0.03
0.004
a
a
0.005
0.0006
0.012
0.0014
c
0.005
0.0006
Residual
oil
No. 6
0.0001
0.00001
0.0003
0.00004
a
a
0.00004
5x10-6
0.00009
1.1x10-5
c
3x10-5
4x10-6
1. Emission factors are calculated for dispensed fuel temperature of 60°F.
2. The example gasoline has an RVP of 10 psia.
3. The example crude oil has an RVP of 5 psia.
a. Not normally used.
b. See Table 4.4-2 for these emission factors.
c. Not Available.
Emissions from controlled loading operations can be calculated by multiplying the uncontrolled
emission rate calculated in Equations (1) and (2) by the control efficiency term:
(, efficiency
-
4.4.2.3 Sample Calculation - Loading losses from a gasoline tank truck in dedicated balance service
and practicing vapor recovery would be calculated as follows using Equation (1).
4.4-8
EMISSION FACTORS
4/77
-------
-------
Design basis:
Tank truck volume is 8000 gallons
Gasoline RVP is 9 psia
Dispensing temperature is 80° F
Vapor recovery efficiency is 95%
Loading loss equation:
eff
LT =12.46 -™-,.-rdQ
where: S = Saturation factor (see Table 4.4-1) = 1.0
P = True vapor pressure of gasoline (see Figure 4.3-8) = 6.6 psia
M = Molecular weight of gasoline vapors (see Table 4.3-1) ~66
T = Temperature of gasoline = 540° R
eff = The control efficiency = 95%
= 12 6 (1.0) (6.6) (66) / _95_
LI. iZAb^(1-Ioo
= 0.50 lb/103 gal
Total loading losses are
(0.50 lb/103 gal) (8.0 x 103 gal) = 4.0 Ib of hydrocarbon
4.4.2.4 Service Stations - Another major source of evaporative hydrocarbon emissions is the filling
of underground gasoline storage tanks at service stations. Normally, gasoline is delivered to service
stations in large (8000 gallon) tank trucks. Emissions are generated when hydrocarbon vapors in the
underground storage tank are displaced to the atmosphere by the gasoline being loaded into the tank.
As with other loading losses, the quantity of the service station tank loading loss depends on several
variables including the size and length of the fill pipe, the method of filling, the tank configuration,
and the gasoline temperature, vapor pressure, and composition. An average hydrocarbon emission
rate for submerged filling is 7.3 lb/103 gallons of transferred gasoline, and the rate for splash filling
is 11.5 lb/103 gallons of transferred gasoline (Table 4.4-4).4
Emissions from underground tank filling operations at service stations can be reduced by the use of
the vapor balance system (Figure 4.4-5). The vapor balance system employs a vapor return hose which
returns gasoline vapors displaced from the underground tank to the tank truck storage compartments
being emptied. The control efficiency of the balance system ranges from 93 to 100 percent. Hydrocar-
bon emissions from underground tank filling operations at a service station employing the vapor
balance system and submerged filling are not expected to exceed 0.3 lb/103 gallons of transferred
gasoline.
4.4-10 EMISSION FACTORS 4/77
-------
Table4.4-4. HYDROCARBON EMISSIONS FROM GASOLINE
SERVICE STATION OPERATIONS
Emission source
Filling underground tank
Submerged filling
Splash filling
Balanced submerged filling
Underground tank breathing
Vehicle refueling operations
Displacement losses
(uncontrolled)
Displacement losses
(controlled)
Spillage
Emission rate
lb/1Q3gal throughput
7.3
11.5
0.3
1
9
0.9
0.7
kg/10^ liters throughput
0.88
1.38
0.04
0.12
1.08
0.11
0.084
A second source of hydrocarbon emissions from service stations is underground tank breathing.
Breathing losses occur daily and are attributed to temperature changes, barometric pressure changes,
and gasoline evaporation. The type of service station operation also has a large impact on breathing
losses. An average breathing emission rate is 1 lb/103 gallons throughput.5
4.4.2.5 Motor Vehicle Refueling - An additional source of evaporative hydrocarbon emissions at
service stations is vehicle refueling operations. Vehicle refueling emissions are attributable to vapors
displaced from the automobile tank by dispensed gasoline and to spillage. The quantity of displaced
vapors is dependent on gasoline temperature, auto tank temperature, gasoline RVP, and dispensing
rates. Although several correlations have been developed to estimate losses due to displaced vapors,
significant controversy exists concerning these correlations. It is estimated that the hydrocarbon
emissions due to vapors displaced during vehicle refueling average 9 lb/103 gallons of dispensed
me.**
4,5
The quantity of spillage loss is a function of the type of service station, vehicle tank configuration,
operator technique, and operation discomfort indices. An overall average spillage loss is 0.7 lb/103
gallons of dispensed gasoline.6
Control methods for vehicle refueling emissions are based on conveying the vapors displaced from
the vehicle fuel tank to the underground storage tank vapor space through the use of a special hose and
nozzle (Figure 4.4-7). In the "balance" vapor control system, the vapors are conveyed by natural pres-
sure differentials established during refueling. In "vacuum assist" vapor control systems, the convey-
ance of vapors from the auto fuel tank to the underground fuel tank is assisted by a vacuum pump. The
overall control efficiency of vapor control systems for vehicle refueling emissions is estimated to be 88
to 92 percent.4
4/77
Evaporation Loss Sources
4.4-11
-------
SERVICE
STATION
PUMP
RETURNED VAPORS
![ j(L« DISPENSED GASOLINE
Figure 4.4-7. Automobile refueling vapor-recovery system.
References for Section 4.4
1. Burklin, C.E. and R.L. Honerkamp. Revision of Evaporative Hydrocarbon Emission Factors.
Research Triangle Park, N.C. EPA Report No. 450/3-76-039. August 15, 1976.
2. Burklin, Clinton E. et al. Background Information on Hydrocarbon Emissions From Marine
Terminal Operations, 2 Vols., EPA Report No. 450/3-76-038a and b. Research Triangle Park, N.C.
November 1976.
3. American Petroleum Inst., Evaporation Loss Committee. Evaporation Loss From Tank Cars,
Tank Trucks, and Marine Vessels. Washington, D.C. Bull. 2514. 1959.
4. Burklin, Clinton E. et al. Study of Vapor Control Methods For Gasoline Marketing Operations,
2 Vols. Radian Corporation. Austin, Texas. May 1975.
5. Scott Research Laboratories, Inc. Investigation Of Passenger Car Refueling Losses, Final Report,
2nd year program. EPA Report No. APTD-1453. Research Triangle Park, N.C. September 1972.
6. Scott Research Laboratories, Inc. Mathematical Expressions Relating Evaporative Emissions
From Motor Vehicles To Gasoline Volatility, summary report. Plumsteadville, Pennsylvania.
API Publication 4077. March 1971.
4.4-12
EMISSION FACTORS
4/77
-------
5. CHEMICAL PROCESS INDUSTRY
This section deals with emissions from the manufacture and use of chemicals or chemical products.
Potential emissions from many of these processes are high, but because of the nature of the compounds
they are usually recovered as an economic necessity. In other cases, the manufacturing operation is run
as a closed system allowing little or no escape to the atmosphere.
In general, the emissions that reach the atmosphere from chemical processes are primarily gaseous
and are controlled by incineration, adsorption, or absorption. In some cases, paniculate emissions
may also be a problem. The particulates emitted are generally extremely small and require very
efficient treatment for removal. Emission data from chemical processes are sparse. It was therefore
frequently necessary to make estimates of emission factors on the basis of material balances, yields, or
similar processes.
5.1 ADIPIC ACID fay Pain Canova
5.1.1 General1'2
Adipic acid, HOOC(CH2)4COOH, is a white crystalline solid used in the manufacture of synthetic
fibers, coatings, plastics, urethane foams, elastomers, and synthetic lubricants. Ninety percent of all
adipic acid produced in the United States is used in manufacturing Nylon 6,6. Cyclohexane is generally
the basic raw material used to produce adipic acid; however, one plant uses cyclohexanone, which is a
by-product of another process. Phenol has also been utilized, but has proved to be more expensive and
less readily available than cyclohexane.
During adipic acid production, the raw material, cyclohexane or cyclohexanone, is transferred to a
reactor, where it is oxidized at 260 to 330° F (130 to 170° C) to form a cyclohexanol/cyclohexanone
mixture. The mixture is then transferred to a second reactor and oxidized with nitric acid and a cata-
lyst (usually a mixture of cupric nitrate and ammonium vanadate) at 160 to 220° F (70 to 100° C) to
form adipic acid. The chemistry of these reactions is shown below.
M
H2CCH2
HoC-CHo-COOH
+ (a)HN03 *| + (b)NOx+(c) H20
H2CCH2 H2C-CH2-COOH
V
H2
Cyclohexanone + Nitric acid •- Adipic acid + Nitrogen oxides + Water
HOH
H26hH2
2 2
H2C-CH2-COOH
+ (x) HN03 | + (y) NOX + (z) H20
42 H2C-CH2-COOH
H2
Cyclohexanol + Nitric acid *• Adipic acid + Nitrogen oxides + Water
4/77 Chemical Process Industry 5.1-1
-------
Dissolved NOX gas plus any light hydrocarbon by-products are stripped from the adipic acid/nitric
acid solution with air and steam. Various organic acid by-products, namely acetic acid, glutaric acid,
and succinic acid, are also formed and may be recovered and sold by some plants.
The adipic acid/nitric acid solution is then chilled, and sent to a crystallizer where adipic acid
crystals are formed. The solution is centrifuged to separate the crystals. The remaining solution is sent
to another crystallizer, where any residual adipic acid is crystallized and centrifugally separated. The
crystals from the two centrifuges are combined, dried, and stored. The remaining solution is distilled
to recover nitric acid, which is routed back to the second reactor for re-use. Figure 5.1-1 presents a
general schematic of the adipic acid manufacturing process.
5.1.2 Emissions and Controls
Nitrogen oxides, hydrocarbons, and carbon monoxide are the major pollutants produced in adipic
acid production. The cyclohexane reactor is the largest source of CO and HC, and the nitric acid reactor
is the predominant source of NO*. Particulate emissions are low because baghouses are generally
employed for maximum product recovery and air pollution control. Figure 5.1-1 shows the points of
emission of these pollutants.
The most significant emissions of HC and CO come from the cyclohexane oxidation unit, which is
equipped with high- and low-pressure scrubbers. Scrubbers have a 90 percent collection efficiency of
HC and are used for economic reasons to recover expensive hydrocarbons as well as for pollution
control. Thermal incinerators, flaring, and carbon absorbers can all be used to limit HC emissions
from the cyclohexane oxidation unit with greater than 90 percent efficiency. CO boilers control CO
emissions with 99.99 percent efficiency and HC emissions with practically 100 percent efficiency. The
combined use of a CO boiler and a pressure scrubber results in essentially complete HC and CO con-
trol.
Three methods are presently used to control emissions from the NOX absorber: water scrubbing,
thermal reduction, and flaring or combustion in a powerhouse boiler. Water scrubbers have a low
collection efficiency of approximately 70 percent because of the extended length of time needed to
remove insoluble NO in the absorber offgas stream. Thermal reduction, in which offgases containing
NOX are heated to high temperatures and reacted with excess fuel in a reducing atmosphere, operates
at up to 97.5 percent efficiency and is believed to be the most effective system of control. Burning off-
gas in a powerhouse or flaring has an estimated efficiency of 70 percent.
Emission factors for adipic acid manufacture are listed in Table 5.1-1.
5.1-2 EMISSION FACTORS 4/77
-------
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Chemical Process Industry
5.1-3
-------
Table 5.1-1". EMISSION FACTORS FOR ADIPIC ACID MANUFACTURED
EMISSION FACTOR RATING: B
Process
Raw material storage
Uncontrolled
Cyclohexane oxidation
Uncontrolled0
W/boiler
W/thermal incinerator^
W/flarmge
W/carbon absorber'
W/scrubber plus boiler
Nitric acid reaction
UncontrollPdS
W/water scrubber"
W/thermal reduction'
W/flanng or combustion"
Adipic acid lefmmgl
Uncontrolled^
Adipic acid drying, loading,
and storage
Uncontrolled^
Particulate
Ib/ton
0
0
0
0
0
0
0
0
0
0
0
<0 1
0.8
kg/MT
0
0
0
0
0
Nitrogen J
oxides'3 ' Hydrocaibon
Ib/ton
0
0
0
0
0
0 0
0 0
0 53
0
0
0
<0 1
04
16
kg/MT Ib/ton
0 ' 22
0 ; 40
0 Meg1
0 Neg
0 4
0 2
0 Neg
27 0
8 0
1 0.5 0
16 , 8 0
06 03 05
0
0 , 0
kg/VIT
1 1
2C
Ne]
Neg
2
1
Neg
0
0
0
0
03
0
Carbon monoxide
Ib/ton
kg'MT
0 0
115
1
Neg
12
58
0 5
Neg
6
115 ' 58
Neg i Neg
0 , 0
0 0
0 . 0
0 0
0 , 0
0
0
aEmission factors are in units of pounds of pollutant per ton and kilograms of pollutant per metric ton of adipic acid produced.
b|\IOx is in the form of NO and NO2- Although large quantities of IM20 are also produced, N2O is not considered a criteria
pollutant and is not, therefore, included in these factors.
cUncontrolled emission factors are after scrubber processing since hydrocarbon recovery using scrubbers is an integral part of
adipic acid manufacturing.
dA thermal incinerator is assumed to reduce HC and CO emissions by approximately 99.99%.
eA flaring system is assumed to reduce HC and CO emissions by 90%.
fA carbon absorber is assumed to reduce HC emissions by 94% and to be ineffective in reducing CO emissions.
9Uncontrolled emission factors sre after NOX absorber since nitric acid recovery is an integral part of adipic acid manufacturing.
"Based on estimated 70% control.
'Based on estimated 97.5% control.
IRefining includes chilling, crystallization, centrifuging, and purification.
kParticulate emission factors are after baghouse control device.
Negligible.
References for Section 5.1
1. Screening Study to Determine Need for Standards of Performance for New Adipic Acid Plants.
GCA/Technology Division, Bedford, Mass. Prepared for Environmental Protection Agency,
Research Triangle Park, N.C. under Contract No. 68-02-1316. July 1976.
2. Kirk-Othmer Encyclopedia of Chemical Technology. Adipic Acid. Vol. 1, 2nd Ed. New York,
Interscience Encyclopedia, Inc. 1967. pp. 405-420.
5.1-4
EMISSION FACTORS
4/77
-------
5.2 AMMONIA
5.2.1 Process Description1
The manufacture of ammonia (NI^) is accomplished primarily by the catalytic reaction of hydrogen and
nitrogen at high temperatures and pressures. In a typical plant a hydrocarbon feed stream (usually natural gas) is
desulfurized, mixed with steam, and catalytically reformed to carbon monoxide and hydrogen. Air is introduced
into the secondary reformer to supply oxygen and provide a nitrogen to hydrogen ratio of 1 to 3. The gases then
enter a two-stage shift converter that allows the carbon monoxide to react with water vapor to form carbon
dioxide and hydrogen. The gas stream is next scrubbed to yield a gas containing less than 1 percent CC>2- A
methanator may be used to convert quantities of unreacted CO to inert CH4 before the gases, now largely
nitrogen and hydrogen in a ratio of 1 to 3, are compressed and passed to the converter. Alternatively, the gases
leaving the C02 scrubber may pass through a CO scrubber and then to the converter. The synthesis gases finally
react in the converter to form ammonia.
5.2.2 Emissions and Controls1
When a carbon monoxide scrubber is used before sending the gas to the converter, the regenerator offgases
contain significant amounts of carbon monoxide (73 percent) and ammonia (4 percent). This gas may be
scrubbed to recover ammonia and then burned to utilize the CO fuel valued
The converted ammonia gases are partially recycled, and the balance is cooled and compressed to liquefy the
ammonia. The noncondensable portion of the gas stream, consisting of unreacted nitrogen, hydrogen, and traces
of inerts such as methane, carbon monoxide, and argon, is largely recycled to the converter. To prevent the
accumulation of these inerts, however, some of the noncondensable gases must be purged from the system.
The purge or bleed-off gas stream contains about 15 percent ammonia.2 Another source of ammonia is the
gases from the loading and storage operations. These gases may be scrubbed with water to reduce the atmospheric
emissions. In addition, emissions of CO and ammonia can occur from plants equipped with CO-scrubbing systems.
Emission factors are presented in Table 5.2-1.
2/72 Chemical Process Industry 5.2-1
-------
Table 5.2-1. EMISSION FACTORS FOR AMMONIA MANUFACTURING WITHOUT
CONTROL EQUIPMENT3
EMISSION FACTOR RATING: B
Type of source
Plants with methanator
Purge gasc
Storage and loading0
Plants with CO absorber and
regeneration system
Regenerator exitd
Purge gasc
Storage and loading0
Carbon monoxide
Ib/ton
Neg
-
200
Neg
—
kg/MT
Neg
-
100
Neg
—
Hydrocarbons'3
Ib/ton
90
-
—
90
—
kg/MT
45
-
—
45
—
Ammonia
Ib/ton
3
200
7
3
200
kg/MT
1.5
100
3.5
1.5
100
References 2 and 3.
^Expressed as methane.
cAmmonia emissions can be reduced by 99 percent by passing through three stages of a packed-tower water scrubber. Hydro-
carbons are not reduced.
A two-stage water scrubber and incineration system can reduce these emissions to a negligible amount.
References for Section 5.2
1. Air Pollutant Emission Factors. Final Report. Resources Research, Incorporated. Reston, Virginia. Prepared
for National Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119.
April 1970.
2. Burns, W.E. and R.R. McMullan. No Noxious Ammonia Odor Here. Oil and Gas Journal, p. 129-131,
February 25, 1967.
3. Axelrod, L.C. and T.E. O'Hare. Production of Synthetic Ammonia. New York, M. W. Kellogg Company.
1964.
5.2-2
EMISSION FACTORS
2/72
-------
5.3 CARBON BLACK by Charles Mann
I
5.3.1 Process Description
Carbon black is produced by the reaction of a hydrocarbon fuel, such as oil or gas, with a limited
supply of combustion air at temperatures of 2500 to 3000° F (1370 to 1650° C). The unburned carbon is
collected as an extremely fine (10- to 400-nm diameter), black, fluffy particle. The three processes for
producing carbon black are the furnace process, thermal process, and channel process. In 1973 the
furnace process accounted for over 90 percent of production; the thermal process, 9 percent; and the
channel process, less than 1 percent. The primary use for carbon black is for strengthening rubber
products (mainly rubber tires); it is also used in printing inks, surface coatings, and plastics.
5.3.1.1 Furnace Process - Furnace black is produced by combustion of hydrocarbon feed in a refrac-
tory-lined furnace. Oil-fired furnaces now predominate. In this process (Figure 5.3-1) a heavy, aromatic
oil feed is preheated and fed into the furnace with about half of the air required for complete com-
bustion and a controlled amount of natural gas. The flue gases, which contain entrained carbon parti-
cles, are cooled to about 450° F (235° C) by passage through heat exchangers and water sprays. The
carbon black is then separated from the gas stream, usually by a fabric filter. A cyclone for primary
collection and particle agglomeration may precede the filter. A single collection system often serves a
number of furnaces that are manifolded together.
The recovered carbon black is finished to a marketable product by pulverizing and wet pelletizing
to increase bulk density. Water from the wet pelletizer is driven off in an indirect-fired rotary dryer.
The dried pellets are then conveyed to bulk storage. Process yields range from 35 to 65 percent, de-
pending on the particle size of the carbon black produced and the efficiency of the process. Furnace
designs and operating characteristics influence the particle size of the oil black. Generally, yields are
highest for large particle blacks and lowest for small particle sizes.
The older gas-furnace process is basically the same as the oil-furnace process except that a light
hydrocarbon gas is the primary feedstock and furnace designs are different. Some oil may also be
added to enrich the gas feed. Yields range from 10 to 30 percent, which is much less than in the oil
process, and comparatively coarser particles (40- to 80-nm diameter compared to 20- to 50-nm diameter
for oil-furnace blacks) are produced. Because of the scarcity of natural gas and the comparatively low
efficiency of the gas process, carbon black production by this method has been declining.
5.3.1.2 Thermal Process - The thermal process is a cyclic operation in which natural gas is thermally
decomposed to carbon particles, hydrogen, methane, and a mixture of other hydrocarbons. To start
the cycle, natural gas is burned to heat a brick checkerwork in the process furnace to about 3000° F
(1650°C). After this temperature is reached, the air supply is cut off, the furnace stack is closed, and
natural gas is introduced into the furnace. The natural gas is decomposed by the heat from the hot
bricks. When the bricks become cool, the natural gas flow is shut off. The effluent gases, containing
the thermal black particles, are flushed out of the furnace and cooled by water sprays to about 250°F
(125° C) before passing through cyclonic collectors and fabric filters, which recover the thermal black.
The effluent gases, consisting of about 90 percent hydrogen, 6 percent methane, and a mixture of
other hydrocarbons, are cooled, compressed, and used as a fuel to reheat the furnaces. Normally, more
than enough hydrogen is produced to make the thermal-black process self-sustaining, and the surplus
hydrogen is used to fire boilers that supply process steam and electric power.
The collected thermal black is pulverized and pelletized to a final product in much the same man-
ner as furnace black. Thermal-process yields are generally high (35 to 60 percent), but the relatively
4/77 Chemical Process Industry 5.3-1
-------
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5.3-2
EMISSION FACTORS
4/77
-------
coarse particles produced (180- to 470-nm diameter) do not have the strong reinforcing properties re-
quired for rubber products.
5,3.1.3 Channel Process - In the channel-black process, natural gas is burned with a limited air supply
in long, low buildings. The flame from this burning impinges on long steel channel sections that swing
continuously over the flame. Carbon black deposited on the channels is scraped off into collecting
hoppers. The combustion gases, containing uncollected solid carbon, carbon monoxide, and other
combustion products, are then vented directly from the building. Yields from the channel-black
process are only 5 percent or less, but very fine particles are produced (10- to 30-nm diameter). Chan-
nel-black production has been declining steadily from its peak in the 1940's. Since 1974 no production
of channel black has been reported.
5.3.2 Emissions and Controls
Emissions from carbon black manufacture include particulates, sulfur compounds, carbon monox-
ide, hydrocarbons, and nitrogen oxides. Trace amounts of polynuclear organic matter (POM) are also
likely to be emitted. Emissions vary considerably from one process to another. Typical emission fac-
tors are given in Table 5.3-1.
The principal source of emissions in the furnace process is the main process vent. The vent stream
consists of the reactor effluent plus quench water vapor vented from the carbon-black recovery system.
Gaseous emissions vary considerably according to the grade of carbon black being produced. Hydro-
carbon and CO emissions tend to be higher for small-particle black production. Sulfur compound
emissions are a function of the feed sulfur content. Table 5.3-1 shows the normal emission ranges to be
expected from these variations in addition to typical average values. Some particulate emissions may
also occur from product transport, drier vents, the bagging and storage area, and spilled and leaked
materials. Such emissions are generally negligible, however, because of the high efficiency of collec-
tion devices and sealed conveying systems used to prevent product loss.
Particulate emissions from the furnace-black process are controlled by fabric filters that recover
the product from process and dryer vents. Particulate emissions control is therefore proportional to
the efficiency of the product recovery system. Some producers may use water scrubbers on the dryer
vent system.
Gaseous emissions from the furnace process may be controlled by CO boilers, incinerators, or
flares. The pellet dryer combustion furnace, which is in essence a thermal incinerator, may also be
employed in a control system. CO boilers, thermal incinerators, or combinations of these devices can
achieve essentially complete oxidation of CO, hydrocarbons, and reduced sulfur compounds in the
process flue gas. Particulate emissions may also be reduced by combustion of some of the carbon black
particles; however, emissions of sulfur dioxide and nitrogen oxides are increased by these combustion
devices.
Generally, emissions from the thermal process are negligible. Small amounts of nitrogen oxides
and particulates may be emitted during the heating part of the process cycle when furnace stacks are
open. Entrainment of carbon particles adhering to the checker brick may occur. Nitrogen oxides may
be formed since high temperatures are reached in the furnaces. During the decomposition portion of
the production cycle, the process is a closed system and no emissions would occur except through leaks.
Considerable emissions result from the channel process because of low efficiency of the process and
the venting of the exhaust gas directly to the atmosphere. Most of the carbon input to the process is lost
as CO, CO2, hydrocarbons, and particulate.
4/77 Chemical Process Industry 5.3-3
-------
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5.3-4
EMISSION FACTORS
4/77
-------
References for Section 5.3
1. Air Pollutant Emission Factors. Final Report. Resources Research, Incorporated. Reston,
Virginia. Prepared for National Air Pollution Control Administration, Durham, N.C., under
Contract Number CPA-22-69-119. April 1970.
2. Drogin, I. Carbon Black. J. Air Pol. Control Assoc. 18:216-228, April 1968.
3. Cox, J.T. High Quality, High Yield Carbon Black. Chem. Eng. 57:116-117, June 1950.
4. Reinke, R.A. and T.A. Ruble. Oil Black. Ind. Eng. Chem. 44:685-694, April 1952.
5. Engineering and Cost Study of Air Pollution Control for the Petrochemical Industry, Volume 1:
Carbon Black Manufacture by the Furnace Process. Houdry Division, Air Products and Chem-
icals, Incorporated. Publication Number EPA-450/3-73-006a. June 1974.
6. Hustvedt, Kent C., Leslie B. Evans, and William M. Vatavuk. Standards Support and Environ-
mental Impact Statement, An Investigation of the Best Systems of Emission Reduction for
Furnace Process Carbon Black Plants in the Carbon Black Industry. U.S. Environmental
Protection Agency, Research Triangle Park, N.C. April 1976.
7. Carbon Black (Oil Black). Continental Carbon Company. Hydrocarbon Processing,, 52:111.
November 1973.
4/77 Chemical Process Industry 5.3-5
-------
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5.4 CHARCOAL
5.4.1 Process Description1
Charcoal is generally manufactured by means of pyrolysis, or destructive distillation, of wood waste from
members of the deciduous hardwood species. In this process, the wood is placed in a retort where it is externally
heated for about 20 hours at 500 to 700°F (260 to 370°C). Although the retort has air intakes at the bottom,
these are only used during start-up and thereafter are closed. The entire distillation cycle takes approximately 24
hours, the last 4 hours being an exothermic reaction. Four units of hardwood are required to produce one unit of
charcoal.
5.4.2 Emissions and Controls1
In the pyrolysis of wood, all the gases, tars, oils, acids, and water are driven off, leaving virtually pure carbon.
All of these except the gas, which contains methane, carbon monoxide, carbon dioxide, nitrogen oxides, and
aldehydes, are useful by-products if recovered. Unfortunately, economics has rendered the recovery of the
distillate by-products unprofitable, and they are generally permitted to be discharged to the atmosphere. If a
recovery plant is utilized, the gas is passed through water-cooled condensers. The condensate is then refined while
the remaining cool, noncondensable gas is discharged to the atmosphere. Gaseous emissions can be controlled by
means of an afterburner because the unrecovered by-products are combustible. If the afterburner operates
efficiently, no organic pollutants should escape into the atmosphere. Emission factors for the manufacture of
charcoal are shown in Table 5.4-1.
Table 5.4-1. EMISSION FACTORS FOR CHARCOAL MANUFACTURING3-*1
EMISSION FACTOR RATING: C
Pollutant
Particulate (tar, oil)
Carbon monoxide
Hydrocarbons0
Crude methanol
Acetic acid
Other gases (HCHO, N2 NO)
Type of operation
With chemical
recovery plant
Ib/ton
320b
10013
60
kg/MT
160b
50b
30
Without chemical
recovery plant
Ib/ton
400
320b
10Qb
152
232
60b
kg/MT
200
16013
50b
76
116
3&
Calculated values based on data in Reference 2.
bEmissions are negligible if afterburner is used.
cExpressed as methane.
^Emission factors expressed in units of tons of charcoal produced.
References for Section 5.4
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National Air
Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Shreve, R.N. Chemical Process Industries, 3rd Ed. New York, McGraw-Hill Book Company. 1967. p. 619..
4/77 Chemical Process Industry 5.4-1
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5.5 CHLOR-ALKALI
5.5.1 Process Description1
Chlorine and caustic are produced concurrently by the electrolysis of brine in either the diaphragm or mercury
cell. In the diaphragm cell, hydrogen is liberated at the cathode and a diaphragm is used to prevent contact of the
chlorine produced at the anode with either the alkali hydroxide formed or the hydrogen. In the mercury cell,
liquid mercury is used as the cathode and forms an amalgam with the alkali metal. The amalgam is removed from
the cell and is allowed to react with water in a separate chamber, called a denuder, to form the alkali hydroxide
and hydrogen.
Chlorine gas leaving the cells is saturated with water vapor and then cooled to condense some of the water.
The gas is further dried by direct contact with strong sulfuric acid. The dry chlorine gas is then compressed for
in-plant use or is cooled further by refrigeration to liquefy the chlorine.
Caustic as produced in a diaphragm-cell plant leaves the cell as a dilute solution along with unreacted brine.
The solution is evaporated to increase the concentration to a range of 50 to 73 percent; evaporation also
precipitates most of the residual salt, which is then removed by filtration. In mercury-cell plants, high-purity
caustic can be produced in any desired strength and needs no concentration.
5.5.2 Emissions and Controls1
Emissions from diaphragm- and mercury-cell chlorine plants include chlorine gas, carbon dioxide, carbon
monoxide, and hydrogen. Gaseous chlorine is present in the blow gas from liquefaction, from vents in tank cars
and tank containers during loading and unloading, and from storage tanks and process transfer tanks. Other
emissions include mercury vapor from mercury cathode cells and chlorine from compressor seals, header seals,
and the air blowing of depleted brine in mercury-cell plants.
Chlorine emissions from chlor-alkali plants may be controlled by one of three general methods: (l)use of the
gas in other plant processes, (2) neutralization in alkaline scrubbers, and (3) recovery of chlorine from effluent gas
streams. The effect of specific control practices is shown to some extent in the table on emission factors (Table
5.5-1).
References for Section 5.5
1. Atmospheric Emissions from Chlor-Alkali Manufacture. U.S. EPA, Air Pollution Control Office. Research
Triangle Park, N.C. Publication Number AP-80. January 1971.
2. Duprey, R.L. Compilation of Air Pollutant Emission Factors. U.S. DREW, PHS, National Center for Air
Pollution Control. Durham, N.C. PHS Publication Number 999-AP-42. 1968. p. 49.
2/72 Chemical Process Industry 5.5-1
-------
Table 5.5-1. EMISSION FACTORS FOR CHLOR-ALKALI PLANTS3
EMISSION FACTOR RATING: B
Type of source
Liquefaction blow gases
Diaphragm cell, uncontrolled
Mercury cell"3, uncontrolled
Water absorber
Caustic or lime scrubber
Loading of chlorine
Tank car vents
Storage tank vents
Air-blowing of mercury-cell brine
Chlorine gas
lb/100tons
2,000 to 10,000
4,000 to 16,000
25 to 1,000
1
450
1,200
500
kg/100MT
1,000 to 5, 000
2,000 to 8,000
12.5 to 500
0.5
225
600
250
References 1 and 2.
^Mercury cells lose about 1.5 pounds mercury per 100 tons (0.75 kg/100 MT) of chlorine liquefied.
5.5-2
EMISSION FACTORS
2/72
-------
.6 EXPLOSIVES by Charles Mann
5.6.1 General1
An explosive is a material that, under the influence of thermal or mechanical shock, decomposes rapidly and
spontaneously with the evolution of large amounts of heat and gas. Explosives fall into two major categories:
high explosives and low explosives. High explosives are further subdivided into initiating or primary high
. explosives and secondary high explosives. Initiating high explosives are very sensitive and are generally used in
small quantities in detonators and percussion caps to set off larger quantities of secondary high explosives.
Secondary high explosives, chiefly nitrates, nitro compounds, and nitramines, are much less sensitive to
. mechanical or thermal shock, but explode with great violence when set off by an initiating explosive. The chief
secondary high explosives manufactured for commercial and military use are ammonium nitrate blasting agents
and 2.4. 6,-trinitrotoluene (TNT). Low explosives, such as black powder and nitrocellulose, undergo relatively
slow autocombustion when set off and evolve large volumes of gas in a definite and controllable manner. A
multitude of different types of explosives are manufactured. As examples of the production of a high explosive
and a low explosive, the production of TNT and nitrocellulose are discussed in this section.
5.6.2 TNT Production !'3
TNT may be prepared by either a continuous process or a batch, three-stage nitration process using toluene,
nitric acid, and sulfuric acid as raw materials. In the batch process, a mixture of oleum (fuming sulfuric acid) and
nitric acid that has been concentrated to a 97 percent solution is used as the nitrating agent. The overall reaction
may be expressed as:
CH3
+ 3HON02 + H2S04-^02N~To JN02 + 3H20 + H2SO4 (1)
NO2
Toluene Nitric Sulfuric TNT Water Sulfuric
acid acid acid
Spent acid from the nitration vessels is fortified with make-up 60 percent nitric acid before entering the next
nitrator. Fumes from the nitration vessels are collected and removed from the exhaust by an oxidation-
absorption system. Spent acid from the primary nitrator is sent to the acid recovery system in which the sulfuric
and nitric acid are separated. The nitric acid is recovered as a 60 percent solution, which is used for
re fortification of spent acid from the second and third nitrators. Sulfuric acid is concentrated in a drum
concentrator by boiling water out of the dilute acid. The product from the third nitration vessel is sent to the
wash house at which point asymmetrical isomers and incompletely nitrated compounds are removed by washing
with a solution of sodium sulfite and sodium hydrogen sulfite (Sellite). The wash waste (commonly called red
water) from the purification process is discharged directly as a liquid waste stream, is collected and sold, or is
concentrated to a slurry and incinerated in rotary kilns. The purified TNT is solidified, granulated, and moved to
the packing house for shipment or storage. A schematic diagram of TNT production by the batch process is
shown in Figure 5.6-1.
12/75 Chemical Process Industry 5.6-1
-------
«*
o
c
ca
CD
o
O
o
+-I
CD
o
'
o
E
2
O)
_O
LL
cq
tn
QJ
5.6-2
EMISSION FACTORS
12/75
-------
5.6.3 Nitrocellulose Production
Nitrocellulose is prepared by the batch-type "mechanical dipper" process. Cellulose, in the form of cotton
linters, fibers, or specially prepared wood pulp, is purified, bleached, dried, and sent to a reactor (niter pot)
containing a mixture of concentrated nitric acid and a dehydrating agent such as sulfuric acid, phosphoric acid,
or magnesium nitrate. The overall reaction may be expressed as:
C6H702(OH)3 + 3HON02 + H2S04 * C6H702(ON02)3 + 3 H20 + H2S04 (2)
Cellulose Nitric Sulfuric Nitrocellulose Water Sulfuric
acid acid acid
When nitration is complete, the reaction mixtures are centrifuged to remove most of the spent acid. The spent
acid is fortified and reused or otherwise disposed of. The centrifuged nitrocellulose undergoes a series of water
washings and boiling treatments for purification of the final product.
5.6.4 Emissions and Controls2'3'5
The major emissions from the manufacture of explosives are nitrogen oxides and acid mists, but smaller
amounts of sulfuric oxides and particulates may also be emitted. Emissions of nitrobodies (nitrated organic
compounds) may also occur from many of the TNT process units. These compounds cause objectionable odor
problems and act to increase the concentration of acid mists. Emissions of sulfur oxides and nitrogen oxides from
the production of nitric acid and sulfuric acid used for explosives manufacturing can be considerable. It is
imperative to identify all processes that may take place at an explosives plant in order to account for all sources
of emissions. Emissions from the manufacture of nitric and sulfuric acid are discussed in other sections of this
publication.
In the manufacture of TNT, vents from the furne recovery system, sulfuric acid concentrators, and nitric acid
concentrators are the principal sources of emissions. If open burning or incineration of waste explosives is
practiced, considerable emissions may result. Emissions may also result from the production of Sellite solution
and the incineration of red water. Many plants, however, now sell the red water to the paper industry where it is
of economic importance.
Principal sources of emissions from nitrocellulose manufacture are from the reactor pots and centrifuges,
spent acid concentrators, and boiling tubs used for purification.
The most important factor affecting emissions from explosives manufacture is the type and efficiency of the
manufacturing process. The efficiency of the acid and fume recovery systems for TNT manufacture will directly
affect the atmospheric emissions. In addition, the degree to which acids are exposed to the atmosphere during
the manufacturing process affects the NOX and SOX emissions. For nitrocellulose production, emissions are
influenced by the nitrogen content and the desired quality of the final product. Operating conditions will also
affect emissions. Both TNT and nitrocellulose are produced in batch processes. Consequently, the processes may
never reach steady state and emission concentrations may vary considerably with time. Such fluctuations in
emissions will influence the efficiency of control methods. Several measures may be taken to reduce emissions
from explosives manufacturing. The effects of various control devices and process changes upon emissions, along
with emission factors for explosives manufacturing, are shown in Table 5.6-1. The emission factors are all related
to the amount of product produced and are appropriate for estimating long-term emissions or for evaluating
plant operation at full production conditions. For short time periods or for plants with intermittent operating
schedules, the emission factors in Table 5.6-1 should be used with caution, because processes not associated with
the nitration step are often not in operation at the same time as the nitration reactor.
12/75 Chemical Process Industry 5.6-3
-------
Table 5.6-1. EMISSION FACTORS FOR
EMISSION FACTOR
Type of process
TNT - batch process'3
Nitration reactors
Fume recovery
Acid recovery
Nitric acid concentrators
Su If uric acid concentrators0
Electrostatic
precipitator (exit)
Electrostatic precipitator
with scrubber0"
Red water incinerator
Uncontrolled6
Wet scrubber
Sellite exhaust
TNT - continuous process^
Nitration reactors
Fume recovery
Acid recovery
Red water incinerator
NitrocelluloseS
Nitration reactors'1
Nitric acid concentrator
Sulfuric acid concentrator
Boiling tubs
Particulates
Ib/ton
—
-
-
-
—
25(0.03-126)
1
-
—
-
0.25(0.03-0.05)
—
—
-
—
kg/MT
—
-
-
—
—
12.5(0.015-63)
0.5
-
—
-
0.13(0.015-0.025)
—
—
—
—
Sulfur oxides
(S02)
Ib/ton
—
-
-
14(4-40)
Meg.
2(0.05-3.5)
2(0.05-3.5)
59(0.01-177)
—
-
0.24(0.05-0.43)
1.4(0.8-2)
_
68(0.4-135)
_
kg/MT
-
-
-
7(2-20)
Neg.
1(0.025-1.75)
1(0.025-1.75)
29.5(0.005-88)
-
--
0.12(0.025-0.22)
0.7(0.4-1)
—
34(0.2-67)
—
aFor some processes considerable variations in emissions have been reported. The average of the values reported is shown first,
with the ranges given in parentheses. Where only one number is given, only one source test was available.
Reference 5.
cAcid mist emissions influenced by nitrobody levels and type of fuel used in furnace.
dIMo data available for NOX emissions after the scrubber. It is assumed that NOX emissions are unaffected by the scrubber.
5.6-4
EMISSION FACTORS
12/75
-------
EXPLOSIVES MANUFACTURING3
IATING: C
Nitrogen oxides
(N02)
Ib/ton
25(6-38)
55(1-136)
37(16-72)
40(2-80)
40(2-80)
26(1.5-101)
5
—
8(6.7-10)
3(1-4.5)
(7(6.1-8.4)
14(3.7-34)
14(10-18)
2
kg/MT
12.5(3-19)
27.5(0.5-68)
18.5(8-36)
20(1-40)
20(1-40)
13(0.75-50)
2.5
-
4(3.35-5)
1.5(0.5-2.25)
3.5(3-4.2)
7(1.85-17)
7(5-9)
1
Nitric acid mist
(100%HNO3)
Ib/ton
1(0.3-1.9)
92(0.01-275)
-
-
-
-
—
1(0.3-1.9)
0.02(0.01-0.03)
-
19(0.5-36)
kg/MT
0.5(0.5-0.95)
46(0.005-137)
-
-
-
-
—
0.5(0.15-0.95)
0.01(0.005-0.015)
-
9.5(0.25-18)
__
Sulfuric acid mist
(100%H2SO4)
Ib/ton
-
9(0.3-27)
65(1-188)
5(4-6)
-
6(0.6-16)
-
-
0.3
kg/MT
-
4.5(0.15-13.5)
32.5(0.5-94)
2.5(2-3)
-
3(0.3-8)
-
-
0.3
eUse low end of range for modern, efficient units and high end of range for older, less efficient units.
Apparent reductions in NOX and paniculate after control may not be significant because these values are based on only one
test result.
9 Reference 4.
For product with low nitrogen content (12 percent), use high end of range. For products with higher nitrogen content, use lower
end of range.
12/75
Chemical Process Industry
5.6-5
-------
References for Section 5.6
1. Shreve, R.N. Chemical Process Industries, 3rd Ed. New York, McGraw-Hill Book Company, 1967. p. 383-395.^
2. Unpublished data on emissions from explosives manufacturing, National Air Pollution Control Administration,
Office of Criteria and Standards, Durham, N.C. June 1970.
3. Higgins, F.B., Jr., et al. Control of Air Pollution From TNT Manufacturing. (Presented at 60th annual meeting
of Air Pollution Control Association. Cleveland. June 1967. Paper 67-111.)
4. Air Pollution Engineering Source Sampling Surveys, Radford Army Ammunition Plant. U.S. Army
Environmental Hygiene Agency, Edgewood Arsenal, Md,
5. Air Pollution Engineering Source Sampling Surveys, Volunteer Army Ammunition Plant and Joliet Army
Ammunition Plant. U.S. Army Environmental Hygiene Agency, Edgewood Arsenal, Md.
5.6-6 EMISSION FACTORS 12/75
-------
5.7 HYDROCHLORIC ACID
Hydrochloric acid is manufactured by a number of different chemical processes. Approximately 80 percent of
the hydrochloric acid, however, is produced by the by-product hydrogen chloride process, which will be the only
process discussed in this section. The synthesis process and the Mannheim process are of secondary importance.
5.7.1 Process Description1
By-product hydrogen chloride is produced when chlorine is added to an organic compound such as benzene,
toluene, and vinyl chloride. Hydrochloric acid is produced as a by-product of this reaction. An example of a
process that generates hydrochloric acid as a by-product is the direct chlorination of benzene. In this process
benzene, chlorine, hydrogen, air, and some trace catalysts are the raw materials that produce chlorobenzene. The
gases from the reaction of benzene and chlorine consist of hydrogen chloride, benzene, chlorobenzenes, and air.
These gases are first scrubbed in a packed tower with a chilled mixture of monochlorobenzene and
dichlorobenzene to condense and recover any benzene or chlorobenzene. The hydrogen chloride is then absorbed
in a falling film absorption plant.
5.7.2 Emissions
The recovery of the hydrogen chloride from the chlorination of an organic compound is the major source of
hydrogen chloride emissions. The exit gas from the absorption or scrubbing system is the actual source of the
hydrogen chloride emitted. Emission factors for hydrochloric acid produced as by-product hydrogen chloride are
presented in Table 5.7-1.
Table 5.7-1. EMISSION FACTORS FOR HYDROCHLORIC
ACID MANUFACTURING3
EMISSION FACTOR RATING: B
Type of process
By-product hydrogen chloride
With final scrubber
Without final scrubber
Hydrogen chloride emissions
Ib/ton
0.2
3
kg/MT
0.1
1.5
aRefer
Reference for Section 5.7
1. Atmospheric Emissions from Hydrochloric Acid Manufacturing Processes. U.S. DHEW, PHS, CPEHS,
National Air Pollution Control Administration. Durham, N.C. Publication Number AP-54. September 1969.
2/72 Chemical Process Industry 5.7-1
-------
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5.8 HYDROFLUORIC ACID
5.8.1 Process Description'
All hydrofluoric acid in the United States is currently produced by the reaction of acid-grade fluorspar with
sulfuric acid for 30 to 60 minutes in externally fired rotary kilns at a temperature of 400° to 500°F (204° to
260°C).2-3'4 The resulting gas is then cleaned, cooled, and absorbed in water and weak hydrofluoric acid to form
a strong acid solution. Anhydrous hydrofluoric acid is formed by distilling 80 percent hydrofluoric acid and
condensing the gaseous HF which is driven off.
5.8.2 Emissions and Controls1
Air pollutant emissions are minimized by the scrubbing and absorption systems used to purify and recover the
HF. The initial scrubber utilizes concentrated sulfuric acid as a scrubbing medium and is designed to remove dust,
SCb, 803, sulfuric acid mist, and water vapor present in the gas stream leaving the primary dust collector. The
exit gases from the final absorber contain small amounts of HF, silicon tetrafluoride (SiF^, CC>2, and SC>2 and
may be scrubbed with a caustic solution to reduce emissions further. A final water ejector, sometimes used to
draw the gases through the absorption system, will reduce fluoride emissions. Dust emissions may also result from
raw fluorspar grinding and drying operations. Table 5.8-1 lists the emission factors for the various operations.
Table 5.8-1. EMISSION FACTORS FOR HYDROFLUORIC ACID MANUFACTURING3
EMISSION FACTOR RATING: C
Type of operation
Rotary kiln
Uncontrolled
Water scrubber
Grinding and drying
of fluorspar
Fluorides
Ib/ton acid
50
0.2
-
kg/MT acid
25
0.1
-
Participates
Ib/ton fluorspar
—
—
20b
kg/MT fluorspar
—
_
10b
References 2 and 5.
Factor given for well-controlled plant.
2/72
Chemical Process Industry
5.8-1
-------
References for Section 5.8
1. Air Pollutant Emission Factors. Final Report. Resources Research Inc., Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-1 19. April 1970.
2. Rogers, W.E. and K. Muller. Hydrofluoric Acid Manufacture. Chem. Eng. Progr. 59:85-88, May 1963.
3. Heller, A.N., S.T. Cuffe, and D.R. Goodwin. Inorganic Chemical Industry. In: Air Pollution Engineering
. Manual. Danielson, J.A. (ed.). U.S. DHEW, PHS. National Center for Air Pollution Control. Cincinnati, Ohio.
Publication Number 999-AP-40. 1967. p. 197-198.
4. Hydrofluoric Acid. Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 9. New York, John Wiley and
Sons, Inc. 1964. p. 444-485.
5. Private Communication between Resources Research, Incorporated, and E.I. DuPont de Nemours and
Company. Wilmington, Delaware. January 13, 1970.
5.8-2 EMISSION FACTORS 2/72
-------
5.9 NITRIC ACID Revised by William Vatavuk
5.9.1 Process Description
5.9.1.1 Weak Acid Production1 - Nearly all the nitric acid produced in the United States is manufactured by the
high-pressure catalytic oxidation of ammonia (Figure 5.9-1). Typically, this process consists of three steps, each
of which corresponds to a distinct chemical reaction. First, a 1:9 ammonia-air mixture is oxidized at high
temperature and pressure (6.4 to 9.2 atmospheres), as it passes through a platinum-rhodium catalyst, according to
the reaction:
4NH3 + 502 —»- 4NO + 6H20 (1)
Ammonia Oxygen Nitric Water
oxide
After the process stream is cooled to 100°F (38°C) or less by passage through a cooler-condenser, the nitric oxide
reacts with residual oxygen:
2ND + 02 -*- 2NO2 -*7" N204
Nitrogen Nitrogen (2)
dioxide tetroxide
Finally, the gases are introduced into a bubble-cap plate absorption column where they are contacted with a
countercurrent stream of water. The exothermic reaction that occurs is:
3N02 + H20 -*- 2HN03 + NO
Nitric acid (3)
50 to 70% aqueous
The production of nitric oxide in reaction (3) necessitates the introduction of a secondary air stream into the
column to effect its oxidation to nitrogen dioxide, thereby perpetuating the absorption operation.
The spent gas flows from the top of the absorption tower to an entrainment separator for acid mist removal,
through the ammonia oxidation unit for energy absorption from the ammonia stream, through an expander for
energy recovery, and finally to the stack. In most plants the stack gas is treated before release to the atmosphere
by passage through either a catalytic combustor or, less frequently, an alkaline scrubber.
5.9.1.2 High-Strength Acid Production1 - To meet requirements for high strength acid, the 50 to 70 percent acid
produced by the pressure process is concentrated to 95 to 99 percent at approximately atmospheric pressure. The
concentration process consists of feeding strong sulfuric acid and 60 percent nitric acid to the top of a packed
column where it is contacted by an ascending stream of weak acid vapor, resulting in the dehydration of thf
latter. The concentrated acid vapor that leaves the column passes to a bleacher and countercurrent condense
system to effect condensation of the vapors and separation of the small amounts of nitric oxides and oxygen th'
form as dehydration by-products. These by-products then flow to an absorption column where the nitric oxi- .
mixes with auxiliary air to form nitrogen dioxide, which is, in turn, recovered as weak nitric acid. Finally,
unreacted gases are vented to the atmosphere from the top of the column.
4/73 Chemical Process Industry 5.9-1
-------
AIR
i
COMPRESSOR
EXPANDER
EFFLUENT
STACK
J
CATALYTIC REDUCTION
-
-------
5.9.2 Emissions and Controls1"3
The emissions derived from nitric acid manufacture consist primarily of nitric oxide, which accounts for
visible emissions; nitrogen dioxide; and trace amounts of nitric acid mist. By far, the major source of nitrogen
oxides is the tail gas from the acid absorption tower (Table 5.9-1). In general, the quantity of NOX emissions is
directly related to the kinetics of the nitric acid formation reaction.
The specific operating variables that increase tail gas NOX emissions are: (1) insufficient air supply, which
results in incomplete oxidation of NO; (2) low pressure in the absorber; (3) high temperature in the
cooler-condenser and absorber; (4) production of an excessively high-strength acid; and (5) operation at high
throughput rates, which results in decreased residence time in the absorber.
Aside from the adjustment of these variables, the most commonly used means for controlling emissions is the
catalytic combustor. In this device, tail gases are heated to ignition temperature, mixed with fuel (natural gas,
hydrogen, or a mixture of both), and passed over a catalyst. The reactions that occur result in the successive
reduction of NCh to NO and, then, NO to N2- The extent of reduction of N02 to N^ in the combustor is, in
turn, a function of plant design, type of fuel used, combustion temperature and pressure, space velocity through
the combustor, type and amount of catalyst used, and reactant concentrations (Table 5.9-1).
Comparatively small amounts of nitrogen oxides are also lost from acid concentrating plants. These losses
(mostly N02) occur from the condenser system, but the emissions are small enough to be easily controlled by the
installation of inexpensive absorbers.
Table 5.9-1. NITROGEN OXIDE EMISSIONS FROM NITRIC ACID PLANTS3
EMISSION FACTOR RATING: B
Type of control
Weak acid
Uncontrolled
Catalytic combustor
(natural gas fired)
Catalytic combustor
(hydrogen fired)
Catalytic combustor
(75% hydrogen, 25%
natural gas fired)
High-strength acid
Control
efficiency, %
0
78 to 97
97 to 99.8
98 to 98.5
—
Emissions (N02)b
Ib/ton acid
50 to 55C
2to7d
0.0 to 1.5
0.8 to 1.1
0.2 to 5.0
kg/MT acid
25.0 to 27.5
1.0 to 3.5
0.0 to 0.75
0.4 to 0.55
0.1 to 2.5
References 1 and 2.
Based on 100 percent acid production.
cRange of values taken from four plants measured at following process conditions.
production rate, 120 tons (109 WIT) per day (100 percent rated capacity); absorber exit
temperature, 90° F (32° C); absorber exit pressure, 7.8 atmospheres;acid strength, 57
percent. Under different conditions, values can vary from 43 to 57 Ib/ton (21.5 to 28.5
kg/MT).
"To present a more realistic picture, ranges of values were used instead of averages.
4/73
Chemical Process Industry
5.9-3
-------
Acid mist emissions do not occur from a properly operated plant. The small amounts that may be present in
the absorber exit gas stream are removed by a separator or collector prior to entering the catalytic combustor or
expander.
Finally, small amounts of nitrogen dioxide are lost during the filling of storage tanks and tank cars.
Nitrogen oxide emissions (expressed as NC^) are presented for weak nitric acid plants in table 5.9-1. The
emission factors vary considerably with the type of control employed, as well as with process conditions. For
comparison purposes, the Environmental Protection Agency (EPA) standard for both new and modified plants is
3.0 pounds per ton of 100 percent acid produced (1.5 kilograms per metric ton), maximum 2-hour average,
expressed as NC^.4 Unless specifically indicated as 100 percent acid, production rates are generally given in terms
of the total weight of product (water and acid). For example, a plant producing 500 tons (454 MT) per day of 55
weight percent nitric acid is really producing only 275 tons (250 MT) per day of 100 percent acid.
References for Section 5.9
r
1. Control of Air Pollution from Nitric Acid Plants. Unpublished Report. Environmental Protection Agency,
Research Triangle Park, N.C.
2. Atmospheric Emissions from Nitric Acid Manufacturing Processes. U.S. DHEW, PHS, Division of Air
Pollution. Cincinnati, Ohio. Publication Number 999-AP-27. 1966.
3. Unpublished emission data from a nitric acid plant. U.S. DHEW, PHS, EHS, National Air Pollution Control
Administration, Office of Criteria and Standards. Durham, N.C. June 1970.
4. Standards of Performance for New Stationary Sources. Environmental Protection Agency, Washington, D.C.
Federal Register. 36(247): December 23,1971.
5.9-4 EMISSION FACTORS 4/73
-------
5.10 PAINT AND VARNISH
5.10.1 Paint Manufacturing1
The manufacture of paint involves the dispersion of a colored oil or pigment in a vehicle, usually an oil or
resin, followed by the addition of an organic solvent for viscosity adjustment. Only the physical processes of
weighing, mixing, grinding, tinting, thinning, and packaging take place; no chemical reactions are involved.
These processes take place in large mixing tanks at approximately room temperature.
The primary factors affecting emissions from paint manufacture are care in handling dry pigments, types of
solvents used, and mixing temperature.2-3 About 1 or 2 percent of the solvents is lost even under well-controlled
conditions. Particulate emissions amount to 0.5 to 1.0 percent of the pigment handled.4
5.10.2 Varnish Manufacturing1'3
The manufacture of varnish also involves the mixing and blending of various ingredients to produce a wide
range of products. However, in this case chemical reactions are initiated by heating. Varnish is cooked in either
open or enclosed gas-fired kettles for periods of 4 to 16 hours at temperatures of 200 to 650°F (93 to 340°C).
Varnish cooking emissions, largely in the form or organic compounds, depend on the cooking temperatures
and times, the solvent used, the degree of tank enclosure, and the type of air pollution controls used. Emissions
from varnish cooking range from 1 to 6 percent of the raw material.
To reduce hydrocarbons from the manufacture of paint and varnish, control techniques include condensers
and/or adsorbers on solvent-handling operations, and scrubbers and afterburners on cooking operations.
Emission factors for paint and varnish are shown in Table 5.10-1.
2/72 Chemical Process Industry 5.10-1
-------
Table 5.10-1. EMISSION FACTORS FOR PAINT AND VARNISH MANUFACTURING
WITHOUT CONTROL EQUIPMENT3-11
EMISSION FACTOR RATING: C
Type of
product
Paint
Varnish
Bodying oil
Oleoresinous
Alkyd
Acrylic
Participate
Ib/ton pigment
2
—
—
—
—
kg/MT pigment
1
-
—
-
—
Hydrocarbons0
Ib/ton of product
30
40
150
160
20
kg/MT pigment
15
20
75
80
10
References 2 and 4 through 8.
Afterburners can reduce gaseous hydrocarbon emissions by 99 percent and participates by about 90
percent. A water spray and oil filter system can reduce particulates by about 90 percent,
cExpressed as undefined organic compounds whose composition depends upon the type of varnish or
paint.
References for Section 5.10
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Stenburg, R.L. Atmospheric Emissions from Paint and Varnish Operations. Paint Varn. Prod. p. 61-65 and
111-114, September 1959.
3. Private Communication between Resources Research, Incorporated, and National Paint, Varnish and Lacquer
Association. September 1969.
4. Unpublished engineering estimates based on plant visits in Washington, D.C, Resources Research,
Incorporated. Reston, Va. October 1969.
5. Chatfield, H.E. Varnish Cookers. In: Air Pollution Engineering Manual. Danielson, J. A. (ed.). U.S. DHEW,
PHS, National Center for Air Pollution Control. Cincinnati, Ohio. Publication Number 999-AP-40. 1967. p.
688-695.
6. Lunche, E.G. et al. Distribution Survey of Products Emitting Organic Vapors in Los Angeles County. Chem.
Eng. Progr. 53. August 1957.
\
7. Communication on emissions from paint and varnish operations with G. Sallee, Midwest Research Institute.
December 17, 1969.
8. Communication with Roger Higgins, Benjamin Moore Paint Company. June 25, 1968 .
5.10-2
EMJS&IQJ^LFACTORS
2/72
-------
5.11 PHOSPHORIC ACID
Phosphoric acid is produced by two principal methods, the wet process and the thermal process. The wet
process is usually employed when the acid is to be used for fertilizer production. Thermal-process acid is normally
of higher purity and is used in the manufacture of high-grade chemical and food products.
5.11.1 Wet Process1 '2
In the wet process, finely ground phosphate rock is fed into a reactor with sulfuric acid to form phosphoric
acid and gypsum. There is usually little market for the gypsum produced, and it is handled as waste material in
gypsum ponds. The phosphoric acid is separated from the gypsum and other insolubles by vacuum filtration. The
acid is then normally concentrated to about 50 to 55 percent PiC^. When superphosphoric acid is made, the acid
is concentrated to between 70 and 85 percent ?2
Emissions of gaseous fluorides, consisting mostly of silicon tetrafluoride and hydrogen fluoride, are the major
problems from wet-process acid. Table 5.11-1 summarizes the emission factors from both wet-process acid and
thermal-process acid.
5. 1 1 .2 Thermal Process1
In the thermal process, phosphate rock, siliceous flux, and coke are heated in an electric furnace to produce
elemental phosphorus. The gases containing the phosphorus vapors are passed through an electrical precipitator to
remove entrained dust. In the "one-step" version of the process, the gases are next mixed with air to form P^O^
before passing to a water scrubber to form phosphoric acid. In the "two-step" version of the process, the
phosphorus is condensed and pumped to a tower in which it is burned with air, and the P^C^ formed is hydrated
by a water spray in the lower portion of the tower.
The principal emission from thermal-process acid is P2®5 ac'^ ni'st ^roni tne absorber tail gas. Since all plants
are equipped with some type of acid-mist collection system, the emission factors presented in Table 5.11-1 are
based on the listed types of control.
2/72 Chemical Process Industry 5.11-1
-------
Table 5.11-1. EMISSION FACTORS FOR PHOSPHORIC ACID PRODUCTION
EMISSION FACTOR RATING: B
Source
Wet process (phosphate rock)
Reactor, uncontrolled
Gypsum pond
Condenser, uncontrolled
Thermal process (phosphorus burned0)
Packed tower
Venturi scrubber
Glass-fiber mist eliminator
Wire-mesh mist eliminator
High-pressure-drop mist eliminator
Electrostatic precipitator
Particulates
Ib/ton
—
—
—
4.6
5.6
3.0
2.7
0.2
1.8
kg/MT
—
—
—
2.3
2.8
1.5
1.35
0.1
0.9
Fluorides
Ib/ton
18a
Ib
203
—
—
—
—
—
—
kg/MT
9a
1.1b
10a
—
—
—
—
-
—
References 2 and 3.
bPounds per acre per day (kg/hectare-day); approximately 0.5 acre (0.213 hectare) is
required to produce 1 ton of PO^B daily.
°Reference 4.
References for Section 5.11
1. Duprey, R.L. Compilation of Air Pollutant Emission Factors. U.S. DHEW, PHS, National Center for Air
Pollution Control. Durham, N.C. PHS Publication Number 999-AP-42. 1968. p. 16.
2. Atmospheric Emissions from Wet-Process Phosphoric Acid Manufacture. U.S. DHEW, PHS, EHS, National
Air Pollution Control Administration. Raleigh, N.C. Publication Number AP-57. April 1970.
3. Control Techniques for Fluoride Emissions. Internal document. U.S. EPA, Office of Air Programs. Research
Triangle Park, N.C. 1970.
4. Atmospheric Emissions from Thermal-Process Phosphoric Acid Manufacturing. Cooperative Study Project:
Manufacturing Chemists' Association, Incorporated, and Public Health Service. U.S. DHEW, PHS, National
Air Pollution Control Administration. Durham, N.C. Publication Number AP-48. October 1968.
5.11-2
EMISSION FACTORS
2/72
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5.12 PHTHALIC ANHYDRIDE
5.12.1 General1
by Pam Canova
Phthalic anhydride (PAN) production in the United States in 1972 was 0.9 billion pounds per year;
this total is estimated to increase to 2.2 billion pounds per year by 1985. Of the current production, 50
percent is used for plasticizers, 25 percent for alkyd resins, 20 percent for unsaturated polyester resins,
and 5 percent for miscellaneous and exports. PAN is produced by catalytic oxidation of either ortho-
xylene or naphthalene. Since naphthalene is a higher priced feedstock and has a lower feed utilization
(about 1.0 Ib PAN/lb o-xylene versus 0.97 Ib PAN/lb naphthalene), future production growth is pre-
dicted to utilize o-xylene. Because emission factors are intended for future as well as present applica-
tion, this report will focus mainly on PAN production utilizing o-xylene as the main feedstock.
The processes for producing PAN by o-xylene or naphthalene are the same except for reactors,
catalyst handling, and recovery facilities required for fluid bed reactors.
In PAN production using o-xylene as the basic feedstock, filtered air is preheated, compressed, and
mixed with vaporized o-xylene and fed into the fixed-bed tubular reactors. The reactors contain the
catalyst, vanadium pentoxide, and are operated at 650 to 725°F (340 to 385°C). Small amounts of
sulfur dioxide are added to the reactor feed to maintain catalyst activity. Exothermic heat is removed
by a molten salt bath circulated around the reactor tubes and transferred to a steam generation system.
Naphthalene-based feedstock is made up of vaporized naphthalene and compressed air. It is
transferred to the fluidized bed reactor and oxidized in the presence of a catalyst, vanadium pent-
oxide, at 650 to 725° F (340 to 385° C). Cooling tubes located in the catalyst bed remove the^xothermic
heat which is used to produce high-pressure steam. The reactor effluent consists of PAN vapors, en-
trained catalyst, and various by-products and non-reactant gas. The catalyst is removed by filtering and
returned to the reactor.
The chemical reactions for air oxidation of o-xylene and naphthalene are as follows.
302
3H20
o-xylene + oxygen
phthalic water
anhydride
»^>
1
SN
0
II
- P
C
NX ~ U
>
naphthalene +
2H20 + 2C02
4/77
anhydride
Chemical Process Industry
0
phthalic + water + carbon
anhydride dioxide
5.12,1
-------
The reactor effluent containing crude PAN plus products from side reactions and excess oxygen passes
to a series of switch condensers where the crude PAN cools and crystallizes. The condensers are alter-
nately cooled and then heated, allowing PAN crystals to form and then melt from the condenser tube
fins.
The crude liquid is transferred to a pretreatment section in which phthulic acid is dehydrated to
anhydride. Water, maleic anhydride, and benzoic acid are partially evaporated. The liquid then goes
to a vacuum distillation section where pure PAN (99.8 wt. percent pure) is recovered. The product can
be stored and shipped either as a liquid or a solid (in which case it is dried, flaked, and packaged in
multi-wall paper bags). Tanks for holding liquid PAN are kept at 300°F (150°C) and blanketed with
dry nitrogen to prevent the entry of oxygen (fire) or water vapor (hydrolysis to phthalic acid).
Maleic anhydride is currently the only by-product being recovered.
Figures 1 and 2 show the process flow for air oxidation of o-xylene and naphthalene, respectively.
5.12.2 Emissions and Controls1
Emissions from o-xylene and naphthalene storage are small and presently are not controlled.
The major contributor of emissions is the reactor and condenser effluent which is vented from the
condenser unit. Particulate, sulfur oxides (for o-xylene-based production), and carbon monoxide
make up the emissions, with carbon monoxide comprising over half the total. The most efficient (96
percent) system of control is the combined usage of a water scrubber and thermal incinerator. A
thermal incinerator alone is approximately 95 percent efficient in combustion of pollutants for o-
xylene-based production, and 80 percent efficient for naphthalene-based production. Thermal incin-
erators with steam generation show the same efficiencies as thermal incinerators alone. Scrubbers
have a 99 percent efficiency in collecting particulates, but are practically ineffective in reducing car-
bon monoxide emissions. In naphthalene-based production, cyclones can be used to control catalyst
dust emissions with 90 to 98 percent efficiency.
Pretreatment and distillation emissions—particulates and hydrocarbons—are normally processed
through the water scrubber and/or incinerator used for the main process stream (reactor and con-
denser) or scrubbers alone, with the same efficiency percentages applying.
Product storage in the liquid phase results in small amounts of gaseous emissions. These gas
streams can either be sent to the main process vent gas control devices! or first processed through
sublimation boxes or devices used to recover escaped PAN. Flaking and bagging emissions are negli-
gible, but can be sent to a cyclone for recovery of PAN dust. Exhaust from the cyclone presents no
problem.
Table 5.12-1 gives emission factors for controlled and uncontrolled emissions from the production
of PAN.
5.12-2 EMISSION FACTORS 4/77
-------
^
8
0)
0}
t/1
CD
0)
X
6
o>
'35
3
(D
03
JC.
a.
o
H-
e
CO
O)
CO
CM
r—
LO
OJ
3
CD
4/77
Chemical Process Industry
5.12-3
-------
5.12-4
EMISSION FACTORS
4/77
-------
Table 5.12-1. EMISSION FACTORS FOR PHTHALIC ANHYDRIDE1-8
EMISSION FACTOR RATING: B
Process
Oxidation of o-xylene°
Mam process stream0
Uncontrolled
W/scrubber and thermal
incinerator
W/thermal incinerator
W/mcinerator with
steam generator
Pretreatment
Uncontrolled
W/scrubber and thermal
incinerator
W/thermal incinerator
Distillation
Uncontrolled
W/scrubber and thermal
incinerator
W/thermal incinerator
Oxidation of naphthalene*3
Main process stream0
Uncontrolled
W/thermal incinerator
W/scrubber
Pretreatment
Uncontrolled
W/thermal incinerator
W/scrubber
Distillation
Uncontrolled
W/thermal incinerator
W/scrubber
Particulate
Ib/ton
138d
6
7
7
13*
0.5
0.7
89d
4
4
569.1
11
0.6
5h
1
<0.1
389
8
0.4
kg/MT
69d
3
4
4
6.4*
0.3
0.4
45^
2
2
289.'
6
0.3
2.5"
0.5
<0.1
199
4
0.2
SOX
Ib/ton
9.4e
9.4
9.4
9.4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
kg/MT
4.?e
4.7
4.7
4.7
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC
Ib/ton
0
0
0
0
0
0
0
2.4
<0.1
0.1
0
0
0
0
0
0
10
2
0.1
kg/MT
0
0
0
0
0
0
0
1.2
<0.1
<0.1
0
0
0
0
0
0
5
1
<0.1
CO
Ib/ton
301
12
15
15
0
0
0
0
0
0
100
20
100
0
0
0
0
0
0
kg/MT
151
6
8
8
0
0
0
0
0
0
50
10
50
0
0
0
0
0
0
aEmission factors are in units of pounds of pollutant per ton (kilogram of pollutant per metric ton) of phthalic anhydride
produced.
"Control devices listed are those currently being used by phthalic anhydride plants,
cMain process stream includes the reactor and multiple switch condensers as vented through the condenser unit.
Particulate consists of phthalic anhydride, maleic anhydride, and benzoic acid.
8Emissions change with catalyst age. Value shown corresponds to relatively fresh catalyst. Can be 19 to 25 Ib/ton (9.5 to 13
kg/MT) for aged catalyst.
Particulate consists of phthalic anhydride and maleic anhydride.
9Particulate consists of phthalic anhydride, maleic anhydride, and naphthaquinone.
Particulate is phthalic anhydride.
'Particulate does not include catalyst dust which is controlled by cyclones with an efficiency of 90 to 98 percent.
Reference for Section 5.12
1. Engineering and Cost Study of Air Pollution Control for the Petrochemical Industry. Vol 7:
Phthalic Anhydride Manufacture from Ortho-Xylene. Houdry Division, Air Products and Chemi-
cals, Inc., Marcus Hook, Pa. Prepared for Environmental Protection Agency, Research Triangle
Park, N.C. Publication No. EPA-450/3-73-006-g. July 1975.
4/77 Chemical Process Industry 5.12-5
-------
-------
5.13 PLASTICS
5.13.1 Process Description1
The manufacture of most resins or plastics begins with the polymerization or linking of the basic compound
(monomer), usually a gas or liquid, into high molecular weight noncrystalline solids. The manufacture of the
basic monomer is not considered part of the plastics industry and is usually accomplished at a chemical or
petroleum plant.
The manufacture of most plastics involves an enclosed reaction or polymerization step, a drying step, and a
final treating and forming step. These plastics are polymerized or otherwise combined in completely enclosed
stainless steel or glass-lined vessels. Treatment of the resin after polmerization varies with the proposed use.
Resins for moldings are dried and crushed or ground into molding powder. Resins such as the alkyd resins that are
to be used for protective coatings are normally transferred to an agitated thinning tank, where they are thinned
with some type of solvent and then stored in large steel tanks equipped with water-cooled condensers to prevent
loss of solvent to the atmosphere. Still other resins are stored in latex form as they come from the kettle.
5.13.2 Emissions and Controls1
The major sources of air contamination in plastics manufacturing are the emissions of raw materials or
monomers, emissions of solvents or other volatile liquids during the reaction, emissions of sublimed solids such as
phthalic anhydride in alkyd production, and emissions of solvents during storage and handling of thinned resins.
Emission factors for the manufacture of plastics are shown in Table 5.13-1.
Table 5.13-1. EMISSION FACTORS FOR PLASTICS
MANUFACTURING WITHOUT CONTROLS3
EMISSION FACTOR RATING: E
Type of plastic
Polyvinyl chloride
Polypropylene
Genera!
Part icu late
Ib/ton
35b
3
5 to 10
kg/MT
17.5b
1.5
2.5 to 5
Gases
Ib/ton
17C
0.7d
—
kg/MT
8.5C
0.35d
—
References 2 and 3
Usually controlled with a fabric filter efficiency of 98 to 99
percent
°As vinyl chloride.
dAs propylene.
Much of the control equipment used in this industry is a basic part of the system and serves to recover a
reactant or product. These controls include floating roof tanks or vapor recovery systems on volatile material,
storage units, vapor recovery systems (adsorption or condensers), purge lines that vent to a flare system, and
recovery systems on vacuum exhaust lines.
2/72
Chemical Process Industry
5.13-1
-------
References for Section 5.13
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Unpublished data from industrial questionnaire. U.S. DHEW, PHS, National Air Pollution Control
Administration, Division of Air Quality and Emissions Data. Durham, N.C. 1969. '
3. Private Communication between Resources Research, Incorporated, and Maryland State Department of
Health, Baltimore, Md. November 1969.
5.13-2 EMISSION FACTORS 2/72
-------
5.14 PRINTING INK
5.14.1 Process Description1
There are four major classes of printing ink: letterpress and lithographic inks, commonly called oil or paste
inks; and flexographic and rotogravure inks, which are referred to as solvent inks. These inks vary considerably in
physical appearance, composition, method of application, and drying mechanism. Flexographic and rotogravuic
inks have many elements in common with the paste inks but differ in that they are of very low viscosity, and they
almost always dry by evaporation of highly volatile solvents.2
There are three general processes in the manufacture of printing inks: (1) cooking the vehicle and adding dyes.
(2) grinding of a pigment into the vehicle using a roller mill, and (3) replacing water in the wet pigment pulp b>
an ink vehicle (commonly known as the flushing process).3 The ink "varnish" or vehicle is generally cooked in
large kettles at 200° to 600°F (93° to 315°C) for an average of 8 to 12 hours in much the same way that regular
varnish is made. Mixing of the pigment and vehicle is done in dough mixers or in large agitated tanks. Grinding is
most often carried out in three-roller or five-roller horizontal or vertical mills.
5.14.2 Emissions and Controls1-4
Varnish or vehicle preparation by heating is by far the largest source of ink manufacturing emissions. Cooling
the varnish components -- resins, drying oils, petroleum oils, and solvents - produces odorous emissions. At
about 350°F (175°C) the products begin to decompose, resulting in the emission of decomposition products
from the cooking vessel. Emissions continue throughout the cooking process with the maximum rate of emissions
occuring just after the maximum temperature has been reached. Emissions from the cooking phase can be
reduced by more than 90 percent with the use of scrubbers or condensers followed by afterburners.4-5
Compounds emitted from the cooking of olcoresmous varnish (resin plus varnish) include water vapor, fatty
acids, glycerine, acrolein, phenols, aldehydes, ketones, terpene oils, tcrpcnes, and carbon dioxide. Emissions of
thinning solvents used in flexographic and rotogravure inks may also occur.
The quantity, composition, and rate of emissions from ink manufacturing depend upon the cooking
temperature and time, the ingredients, the method of introducing additives, the degree of stirring, and the extent
of air or inert gas blowing. Particulate emissions resulting from the addition of pigments to the vehicle are
affected by the type of pigment and its particle si/e. Emission factors for the manufacture of printing ink aie
presented in Table 5.14-1.
2/72 Chemical Process Industry 5.14-1
-------
Table 5.14-1. EMISSION FACTORS FOR PRINTING INK
MANUFACTURING3
EMISSION FACTOR RATING: E
Type of process
Vehicle cooking
General
Oils
Oleoresinous
Alkyds
Pigment mixing
Gaseous organic13
Ib/ton
of product
120
40
150
160
-
kg/MT
of product
60
20
75
80
-
Particulates
Ib/ton
of pigment
—
_.
-
—
2
kg/MT
of pigment
—
-
-
-
1
aBased on data from section on pamt and varnish
Emitted as gas, but rapidly condense as the effluent is cooled.
References for Section 5.14
1. Air Pollutant Emission Factors. Final Report. Resources Research Inc. Reston, Va. Prepared for National Air
Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Shreve, R. N. Chemical Process Industries, 3rd Ed. New York, McGraw Hill Book Co. 1967. p. 454-455.
3. Larsen, L.M. Industrial Printing Inks. New York, Reinhold Publishing Company. 1962.
4. Chatfield, H.E. Varnish Cookers. In: Air Pollution Engineering Manual. Danielson, J.A. (ed.). U.S. DHEW,
PHS, National Center for Air Pollution Control. Cincinnati, Ohio. Publication Number 999-AP-40. 1967. p.
688-695.
5. Private communication with Interchemical Corporation, Ink Division. Cincinnati, Ohio. November 10, 1969.
5.14-2
EMISSION FACTORS
2/72
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5.15 SOAP AND DETERGENTS
5.15.1 Soap Manufacture1
The manufacture of soap entails the catalytic hydrolysis of various fatty acids with sodium or potassium
hydroxide to form a glycerol-soap mixture. This mixture is separated by distillation, then neutralized and blended
to produce soap. The main atmospheric pollution problem in the manufacture of soap is odor. and. if a spray
drier is used, a particulate emission problem may also occur. Vent lines, vacuum exhausts, product and raw
material storage, and waste streams are all potential odor sources. Control of these odors may be achieved by
scrubbing all exhaust fumes and, if necessary, incinerating the remaining compounds. Odors emanating from the
spray drier may be controlled by scrubbing with an acid solution.
5.15.2 Detergent Manufacture1
I
The manufacture of detergents generally begins with the sulfuration by sulfuric acid of a fatty alcohol or linear
alkylate. The sulfurated compound is then neutralized with caustic solution (NaOH). and various dyes, perfumes.
and other compounds are added.2'3 The resulting paste or slurry is then sprayed under pressure into a vertical
drying tower where it is dried with a stream of hot air (400° to 500°F or 204° to 260°C). The dried detergent is
then cooled and packaged. The main source of particulate emissions is the spray-drying tower. Odors may also be
emitted from the spray-drying operation and from storage and mixing tanks. Particulate emissions from
spray-drying operations are shown in Table 5.15-1.
Table 5.15-1. PARTICULATE EMISSION FACTORS FOR
SPRAY-DRYING DETERGENTS3
EMISSION FACTOR RATING: B
Control device
Uncontrolled
Cyclone*5
Cyclone followed by:
Spray chamber
Packed scrubber
Venturi scrubber
Overall
efficiency, %
85
92
95
97
Particulate emissions
Ib/ton of
product
90
14
7
5
3
kg/MT of
product
45
7
3.5
2.5
1.5
aBased on analysis of data in References 2 through 6.
Some type of primary collector, such as a cyclone, is considered an
integral part of the spray-drying system.
2/72
Chemical Process Industry
5.15-1
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References for Section 5.15
1. Air Pollutant Emission Factors. Final Report. Resources Research Inc. Reston, Va. Prepared for National Air
Pollution Control Administration, Durham, N.C., under Contract Number CPA--22-69-119. April 1970.
2. Phelps, A.H. Air Pollution Aspects of Soap and Detergent Manufacture. J. Air Pol. Control Assoc.
17(8):505-507, August 1967.
3. Shreve, R.N. Chemical Process Industries. 3rd Ed. New York, McGraw-Hill Book Company. 1967. p.
544-563.
4. Larsen, G.P., G.I. Fischer, and W.J. Hamming. Evaluating Sources of Air Pollution. Ind. Eng. Chem.
45:1070-1074, May 1953.
5. McCormick, P.Y., R.L. Lucas, and D.R. Wells. Gas-Solid Systems. In: Chemical Engineer's Handbook. Perry,
J.H. (ed.). New York, McGraw-Hill Book Company. 1963. p. 59.
6. Private communication with Maryland State Department of Health, Baltimore, Md. November 1969.
5.15-2 EMISSION FACTORS 2/72
-------
5.16 SODIUM CARBONATE (Soda Ash)
5.16.1 Process Description1
Soda ash is manufactured by three processes: (1) the natural or Lake Brine process, (2) the Solvay process
(ammonia-soda), and (3) the electrolytic soda-ash process. Because the Solvay process accounts for over 80
percent of the total production of soda ash, it will be the only one discussed in this section.
In the Solvay process, the basic raw materials are ammonia, coke, limestone (calcium carbonate), and salt
(sodium chloride). The salt, usually in the unpurified form of a brine, is first purified in a series of absorbers by
precipitation of the heavy metal ions with ammonia and carbon dioxide. In this process sodium bicarbonate is
formed. This bicarbonate coke is heated in a rotary kiln, and the resultant soda ash is cooled and conveyed to
storage.
5.16.2 Emissions
The major source of emissions from the manufacture of soda ash is the release of ammonia. Small amounts of
ammonia are emitted in the gases vented from the brine purification system. Intermittent losses of ammonia can
also occur during the unloading of tank trucks into storage tanks. The major sources of dust emissions include
rotary dryers, dry solids handling, and processing of lime. Dust emissions of fine soda ash also occur from
conveyor transfer points and air classification systems, as well as during tank-car loading and packaging. Emission
factors are summarized in Table 5.16-1.
Table 5.16-1. EMISSION FACTORS FOR SODA-ASH
PLANTS WITHOUT CONTROLS
EMISSION FACTOR RATING: D
Type of source
Ammonia recovery3-13
Conveying, transferring.
loading, etc.c
Particulates
Ib/ton
6
fkg/MT
3
Ammonia
Ib/ton
7
-
kg/MT
3.5
-
"Reference 2.
"Represents ammonia loss following the recovery system.
cBased on data in References 3 through 5.
2/72
Chemical Process Industry
5.16-1
-------
References for Section 5.16
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C.,under Contract Number CPA-22-69-119. April 1970.
2. Shreve, R.N. Chemical Process Industries, 3rd Ed. New York, McGraw-Hill Book Company. 1967. p.
225-230.
3. Facts and Figures for the Chemical Process Industries. Chem. Eng. News. 43:51-118 September 6, 1965.
4. Faith, W.L., D.B. Keyes, and R.L. Clark. Industrial Chemicals, 3rd Ed. New York, John Wiley and Sons, Inc.
1965.
5. Kaylor, F.B. Air Pollution Abatement Program of a Chemical Processing Industry. J. Air Pol. Control Assoc.
75:65-67, February 1965.
5.16-2 EMISSION FACTORS 2/72
-------
5.17 SULFURICACID Revised by William Vatavuk
and Donald Carey
5.17.1 Process Description
All sulfuric acid is made by either the lead chamber or the contact process. Because the contact process
accounts for more than 97 percent of the total sulfuric acid production in the United States, it is the only process
discussed in this section. Contact plants are generally classified according to the raw materials charged to them:
(1) elemental sulfur burning, (2) spent acid and hydrogen sulfide burning, and (3) sulfide ores and smelter gas
burning plants. The relative contributions from each type of plant to the total acid production are 68, 18.5, and
13.5 percent, respectively.
All contact processes incorporate three basic operations, each of which corresponds to a distinct chemical
reaction. First, the sulfur in the feedstock is burned to sulfur dioxide:
S + 02 —*- S02.
Sulfur Oxygen Sulfur (1)
dioxide
Then, the sulfur dioxide is catalytically oxidized to sulfur trioxide:
2S02 + 02 —»- 2S03.
Sulfur Oxygen Sulfur (2)
dioxide trioxide
Finally, the sulfur trioxide is absorbed in a strong, aqueous solution of sulfuric acid:
SO3 + H20 —-»- thSO4.
Sulfur Water Sutfuric
trioxide acid
5.17.1.1 Elemental Sulfur-Burning Plants1'2 - Elemental sulfur, such as Frasch-piocess sulfui from oil refineries,
is melted, settled, or filtered to remove ash and is fed into a combustion chamber. The sulfur is burned in clean
air that has been dried by scrubbing with 93 to 99 percent sulfuric acid. The gases from the combustion chamber
are cooled and then enter the solid catalyst (vanadium pentoxide) converter. Usually, 95 to 98 percent of the
sulfur dioxide from the combustion chamber is converted to sulfur trioxide, with an accompanying large
evolution of heat. After being cooled, the converter exit gas enters an absorption tower where the sulfur trioxide
is absorbed with 98 to 99 percent sulfuric acid. The sulfur trioxide combines with the water in the acid and forms
more sulfuric acid.
If oleum, a solution of uncombined S03 in FbSOzj, is produced, S03 from the converter is first passed to an
oleum tower that is fed with 98 percent acid from the absorption system. The gases from the oleum tower are
then pumped to the absorption column where the residual sulfur trioxide is removed.
A schematic diagram of a contact process sulfuric acid plant that burns elemental sulfur is shown in Figure
5.17-1.
4/73 Chemical Process Industry 5.17-1
-------
o
c
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CD
C
c
c
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CO
co
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CD
o
o
o
ro
'c
o
o
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g
o
co
ca
m
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5.17-2
EMISSION FACTORS
4/73
-------
-SPENT ACID
•SULFUR
'FUEL OIL
so?
STRIPPER AIR
.\\\\\\>
BLOWER
TO
ATMOS-
PHERE
98% ACID
"PUMP TANK
Figure 5.17-2. Basic flow diagram of contact-process sulfuric acid plant burning spent acid.
4/73
Chemical Process Industry
5.17-3
-------
5.17.1.2 Spent Acid and Hydrogen Sulfide Burning Plants1'2 - Two types of plants are used to process this lype
of sulfuric acid. In one the sulfur dioxide and other combustion products from the combustion of spent acid
and/or hydrogen sulfide with undried atmospheric air are passed through gas-cleaning and mist-removal
equipment. The gas stream next passes through a drying tower. A blower draws the gas from the drying tower and
discharges the sulfur dioxide gas to the sulfur trioxide converter. A schematic diagram of a contact-process
sulfuric acid plant that burns spent acid is shown in Figure 5.17-2.
In a "wet-gas plant," the wet gases from the combustion chamber are charged directly to the converter with no
intermediate treatment. The gas from the converter flows to the absorber, through which 93 to 98 percent
sulfuric acid is circulating.
5.17.1.3 Sulfide Ores and Smelter Gas Plants - The configuration of this type of plant is essentially the same as
that of a spent-acid plant (Figure 5.17-2) with the primary exception that a roaster is used in place of the
combustion furnace.
The feed used in these plants is smelter gas, available from such equipment as copper converters, reverberatory
furnaces, roasters, and flash smelters. The sulfur dioxide in the gas is contaminated with dust, acid mist, and
gaseous impurities. To remove the impurities the gases must be cooled to essentially atmospheric temperature and
passed through purification equipment consisting of cyclone dust collectors, electrostatic dust and mist
precipitators, and scrubbing and gas-cooling towers. After the gases are cleaned and the excess water vapor is
removed, they are scrubbed with 98 percent acid in a drying tower. Beginning with the drying tower stage, these
plants are nearly identical to the elemental sulfur plants shown in Figure 5.17-1.
5.17.2 Emissions and Controls
5.17.2.1 Sulfur Dioxide1"3 - Nearly all sulfur dioxide emissions from sulfuric acid plants are found in the exit
gases. Extensive testing has shown that the mass of these SC>2 emissions is an inverse function of the sulfur
conversion efficiency (SC>2 oxidized to 803). This conversion is, in turn, affected by the number of stages in the
catalytic converter, the amount of catalyst used, the temperature and pressure, and the concentrations of the
reactants, sulfur dioxide and oxygen. For example, if the inlet SC>2 concentration to the converter were 8 percent
by volume (a representative value), and the conversion temperature were 473°C, the conversion efficiency would
be 96 percent. At this conversion, the uncontrolled emission factor for SC>2 would be 55 pounds per ton (27.5
kg/MT) of 100 percent sulfuric acid produced, as shown in Table 5.17-1. For purposes of comparison, note that
the Environmental Protection Agency performance standard3 for new and modified plants is 4 pounds per ton
(2kg / MT) of 100 percent acid produced, maximum 2-hour average. As Table 5.17-1 and Figure 5.17-3 indicate,
achieving this standard requires a conversion efficiency of 99.7 percent in an uncontrolled plant or the equivalent
S(>2 collection mechanism in a controlled facility. Most single absorption plants have SC'2conversion efficiencies
ranging from 95 to 98 percent.
In addition to exit gases, small quantities of sulfur oxides are emitted from storage tank vents and tank car and
tank truck vents during loading operations; from sulfuric acid concentrators; and through leaks in process
equipment. Few data are available on emissions from these sources.
Of the many chemical and physical means for removing S02 from gas streams, only the dual absorption and
the sodium sulfite-bisulfite scrubbing processes have been found to increase acid production without yielding
unwanted by-products.
5.17-4 EMISSION FACTORS 4/73
-------
Table 5.17-1. EMISSION FACTORS FOR SULFURIC
ACID PLANTS3
EMISSION FACTOR RATING: A
Conversion of S02
to SO3, %
93
94
95
96
97
98
99
99.5
99.7
100
SO 2 emissions
Ib/tonof 100%
H2S04
96
82
70
55
40
27
14
7
4
0
kg/MTof 100%
H2S04
48.0
41.0
35.0
27.5
20.5
13.0
7.0
3.5
2.0
0.0
Reference 1.
bThe following linear interpolation formula can be used for
calculating emission factors for conversion efficiencies between 93
and 100 percent: emission factor (Ib/ton acid) =-13.65 (percent
conversion efficiency) + 1365.
In the dual absorption process, the 863 gas formed in the primary converter stages is sent to a primary
absorption tower where J^SC^ is formed. The remaining unconverted sulfur dioxide is forwarded to the final
stages in the converter, from whence it is sent to the secondary absorber for final sulfur trioxide removal. The
result is the conversion of a much higher fraction of SC>2 to 863 (a conversion of 99.7 percent or higher, on the
average, which meets the performance standard). Furthermore, dual absorption permits higher converter inlet
sulfur dioxide concentrations than are used in single absorption plants because the secondary conversion stages
effectively remove any residual sulfur dioxide from the primary absorber.
Where dual absorption reduces sulfur dioxide emissions by increasing the overall conversion efficiency, the
sodium sulfite-bisulfite scrubbing process removes sulfur dioxide directly from the absorber exit gases. In one
version of this process, the sulfur dioxide in the waste gas is absorbed in a sodium sulfite solution, separated, and
recycled to the plant. Test results from a 750 ton (680 MT) per day plant equipped with a sulfite scrubbing
system indicated an average emission factor of 2.7 pounds per ton (1.35 kg/MT).
15.17.2.2 Acid Mist1"3 - Nearly all the acid mist emitted from sulfuric acid manufacturing can be traced to the
absorber exit gases. Acid mist is created when sulfur trioxide combines with water vapor at a temperature below
the dew point of sulfur trioxide. Once formed within the process system, this mist is so stable that only a small
quantity can be removed in the absorber.
In general, the quantity and particle size distribution of acid mist are dependent on the type of sulfur
feedstock used, the strength of acid produced, and the conditions in the absorber. Because it contains virtually no
water vapor, bright elemental sulfur produces little acid mist when burned; however, the hydrocarbon impurities
in other feedstocks - dark sulfur, spent acid, and hydrogen sulfide — oxidize to water vapor during combustion.
The water vapor, in turn, combines with sulfur trioxide as the gas cools in the system.
4/73
Chemical Process Industry
5.17-5
-------
99.92
10,000
SULFUR CONVERSION, % feedstock sulfur
99.7 99.0
97.0 96.0 95.0 92.9
1.5 2 2.5 3 4 5 6 7 8 9 10 15 20 25 30 40 50 60708090100
S02EMISSIONS, Ib/ton of 100% H2S04 produced
Figure 5.17-3. Sulfuric acid plant feedstock sulfur conversion versus volumetric and
mass SC>2 emissions at various inlet S02 concentrations by volume.
5.17-6
EMISSION FACTORS
4/73
-------
The strength of acid produced-whether oleum or 99 percent sulfuric acid-also affects mist emissions. Oleum
plants produce greater quantities of finer, more stable mist. For example, uncontrolled mist emissions from
oleum plants burning spent acid range from 0.1 to 10.0 pounds per ton (0.05 to 5.0 kg/MX), while those from 98
percent acid plants burning elemental sulfur range from 0.4 to 4.0 pounds per ton (0.2 to 2.0 kg/MT).
Furthermore, 85 to 95 weight percent of the mist particles from oleum plants are less than 2 microns in diam-
eter, compared with only 30 weight percent that are less than 2 microns in diameter from 98 percent acid plants.
The operating temperature of the absorption column directly affects sulfur trioxide absorption and,
accordingly, the quality of acid mist formed after exit gases leave the stack. The optimum absorber operating
temperature is dependent on the strength of the acid produced, throughput rates, inlet sulfur trioxide
concentrations, and other variables peculiar to each individual plant. Finally, it should be emphasized that the
percentage conversion of sulfur dioxide to sulfur trioxide has no direct effect on u:id mist emissions. In Table
5.17-2 uncontrolled acid mist emissions are presented for various sulfuric acid plants.
Two basic types of devices, electrostatic precipitators and fiber mist eliminators, effectively reduce the acid
mist concentration from contact plants to less than the EPA new-source performance standard, which is 0.15
pound per ton (0.075 kg/MT) of acid. Precipitators, if properly maintained, are effective in collecting the mist
particles at efficiencies up to 99 percent (see Table 5.17-3).
The three most commonly used fiber mist eliminators are the vertical tube, vertical panel, and horizontal
dual-pad types. They differ from one another in the arrangement of the fiber elements, which are composed of
either chemically resistant glass or fluorocarbon, and in the means employed to collect the trapped liquid. The
operating characteristics of these three types are compared with electrostatic precipitators in Table 5.17-3.
Table 5.17-2. ACID MIST EMISSION FACTORS FOR SULFURIC
ACID PLANTS WITHOUT CONTROLS3
EMISSION FACTOR RATING: B
Raw material
Recovered sulfur
Bright virgin sulfur
Dark virgin sulfur
Sulfide ores
Spent acid
Oleurn produced,
% total output
Oto 43
0
33 to 100
Oto 25
Oto 77
Emissions'3
Ib/ton acid
0.35 to 0.8
1.7
0.32 to 6.3
1.2 to 7.4
2.2 to 2.7
kg/MT acid
0.1 75 to 0.4
0.85
0.16 to 3.15
0.6 to 3.7
1.1 to 1.35
Reference 1.
Emissions are proportional to the percentage of oleum in the total product. Use
the low end of ranges for low oleum percentage and high end of ranges for high
oleum percentage.
4/73
Chemical Process Industry
5.17-7
-------
Table 5.17-3. EMISSION COMPARISON AND COLLECTION EFFICIENCY OF TYPICAL
ELECTROSTATIC PRECIPITATOR AND FIBER MIST ELIMINATORS"
Control device
Electrostatic
precipitator
Fiber mist eliminator
Tubular
Panel
Dual pad
Particle size
collection efficiency, %
>3^m
99
100
100
100
<3nm
100
95 to 99
90 to 98
93 to 99
Acid mist emissions
98% acid plants0
Ib/ton
0.10
0.02
0.10
0.11
kg/MT
0.05
0.01
0.05
0.055
oleum plants
Ib/ton
0.12
0.02
0.10
0.11
kg/MT
0.06
0.01
0.05
0.055
Reference 2.
Based on manufacturers' generally expected results; calculated for 8 percent sulfur dioxide
concentration in gas converter.
References for Section 5.17
1. Atmospheric Emissions from Sulfuric Acid Manufacturing Processes. U.S. DHEW, PHS, National Air
Pollution Control Administration. Washington, D.C. Publication Number 999-AP-13. 1966.
2. Unpublished report on control of air pollution from sulfuric acid plants. Environmental Protection Agency.
Research Triangle Park, N.C. August 1971.
3. Standards of Performance for New Stationary Sources. Environmental Protection Agency. Washington, D.C.
Federal Register. 36(247): December 23, 1971.
5.17-8
EMISSION FACTORS
4/73
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5.18 SULFUR By William Vatavuk
5.18.1 Process Description
Nearly all of the elemental sulfur produced from hydrogen sulfide is made by the modified Claus process.
The process (Figure 5.18-1) consists of the multi-stage oxidation of hydrogen sulfide according to the following
reaction:
2H2S + O2 >• 2S + 2H2O
Hydrogen Oxygen Sulfur Water
sulfide
In the first step, approximately one-third of the hydrogen sulfide is reacted with air in a pressurized boiler (1.0
to 1.5 atmosphere) where most of the heat of reaction and some of the sulfur are removed. After removal of the
water vapor and sulfur, the cooled gases are heated to between 400 and 500°F, and passed over a "Claus" catalyst
bed composed of bauxite or alumina, where the reaction is completed. The degree of reaction conpletion is a
function of the number of catalytic stages employed. Two stages can recover 92 to 95 percent of the potential
sulfur; three stages, 95 to 96 percent; and four stages, 96 to 97 percent. The conversion to sulfur is ultimately
limited by the reverse reaction in which water vapor recombines with sulfur to form gaseous hydrogen sulfide and
sulfur dioxide. Additional amounts of sulfur are lost as vapor, entrained mist, or droplets and as carbonyl sulfide
and carbon disulfide (0.25 to 2.5 percent of the sulfur fed). The latter two compounds are formed in the
pressurized boiler at high temperature (1500 to 2500°F) in the presence of carbon compounds.
The plant tail gas, containing the above impurities in volume quantities of 1 to 3 percent, usually passes to an
incinerator, where all of the sulfur is oxidized to sulfur dioxide at temperatures ranging from 1000 to 1200 F.
The tail gas containing the sulfur dioxide then passes to the atmosphere via a stack.
5.18.2 Emissions and Controls1'2
Virtually all of the emissions from sulfur plants consist of sulfur dioxide, the main incineration product. The
quantity of sulfur dioxide emitted is, in turn, a function of the number of conversion stages employed, the
process temperature and pressure, and the amounts of carbon compounds present in the pressurized boiler.
The most commonly used control method involves two main steps - conversion of sulfur dioxide to hydrogen
sulfide followed by the conversion of hydrogen sulfide to elemental sulfur. Conversion of sulfur dioxide to
hydrogen sulfide occurs via catalytic hydrogenation or hydrolysis at temperatures from 600 to 700°F. The
products are cooled to remove the water vapor and then reacted with a sodium carbonate solution to yield
sodium hydrosulfide. The hydrosulfide is oxidized to sulfur in solution by sodium vanadate. Finely divided sulfur
appears as a froth that is skimmed off, washed, dried by centrifugation, and added to the plant product. Overall
recovery of sulfur approaches 100 percent if this process is employed. Table 5.18-1 lists emissions from
controlled and uncontrolled sulfur plants.
4/73 Chemical Process Industry 5.18-1
-------
CLEAN GAS
SOUR
GAS
COOLER
COOLER
REACTIVATOR
HEAT
EXCHANGER
GAS PURIFICATION-
H2S, S02, C02, N2, H20
I
AIR
BOILER
S
CONVERTER
STACK
CONVERTER
SCRUBBER
SCRUBBER
SULFUR CONVERSION
(CLAUS SECTION)
Figure 5.18-1. Basic flow diagram of modified Glaus process with two converter stages
used in manufacturing sulfur.
Table 5.18-1. EMISSION FACTORS FOR MODIFIED-CLAUS
SULFUR PLANTS EMISSION FACTOR RATING: D
Number of
catalytic stages
Two, uncontrolled
Three, uncontrolled
Four, uncontrolled
Sulfur removal process
Recovery of
of sulfur,%
92 to 95
95 to 96
96 to 97
99.9
SO2 emissions3
Ib/ton
100% sulfur
21 1 to 348
167 to 211
124 to 167
4.0
kg/MT
100% sulfur
106 to 162
84 to 1 06
62 to 84
2.0
aThe range in emission factors corresponds to the range in the percentage recovery of
sulfur.
References for Section 5.18
1. Beavon, David K. Abating Sulfur Plant Tail Gases. Pollution Engineering. 4(l):34-35. January 1972.
2. Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 19. New York, John Wiley and Sons, Inc. 1969.
5.18-2
EMISSION FACTORS
4/73
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5.19 SYNTHETIC FIBERS
5.19.1 Process Description1
Synthetic fibers are classified into two major categories, semi-synthetic and "true" synthetic. Semi-synthetics,
such as viscose rayon and acetate fibers, result when natural polymeric materials such as cellulose are brought into
a dissolved or dispersed state and then spun into fine filaments. True synthetic polymers, such as Nylon, * Orion,
and Dacron, result from addition and other polymerization reactions that form long chain molecules.
True synthetic fibers begin with the preparation of extremely long, chain-like molecules. The polymer is spun
in one of four ways:^ (1) melt spinning, in which molten polymer is pumped through spinneret jets, the polymer
solidifying as it strikes the cool air; (2) dry spinning, in which the polymer is dissolved in a suitable organic
solvent, and the resulting solution is forced through spinnerets; (3) wet spinning, in which the solution is
coagulated in a chemical as it emerges from the spinneret; and (4) core spinning, the newest method, in which a
continuous filament yarn together with short-length "hard" fibers is introduced onto a spinning frame in such a
way as to form a composite yarn.
5.19.2 Emissions and Controls1
In the manufacture of viscose rayon, carbon disulfide and hydrogen sulfide are the major gaseous emissions.
Air pollution controls are not normally used to reduce these emissions, but adsorption in activated carbon at an
efficiency of 80 to 95 percent, with subsequent recovery of the €82 can be accomplished.3 Emissions of gaseous
hydrocarbons may also occur from the drying of the finished fiber. Table 5.19-1 presents emission factors for
semi-synthetic and true synthetic fibers.
Table 5.19-1. EMISSION FACTORS FOR SYNTHETIC FIBERS MANUFACTURING
EMISSION FACTOR RATING: E
Type of fiber
Semi-synthetic
Viscose rayona'b
True synthetic0
Nylon
Dacron
Hydrocarbons
Ib/ton
-
7
—
kg/MT
-
3.5
—
Carbon
disulfide
Ib/ton
55
-
—
kg/MT
27.5
-
—
Hydrogen
sulfide
Ib/ton
6
-
—
kg/MT
3
-
—
Oil vapor
or mist
Ib/ton
—
15
7
kg/MT
—
7.5
3.5
aReference 4.
^IVIay be reduced by 80 to 95 percent adsorption in activated charcoal.
cReference 5.
*Mention of company or product names does not constitute endorsement by the Environmental Protection
Agency.
2/72
Chemical Process Industry
5.19-1
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References for Section 5.19
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Fibers, Man-Made. In: Kirk-Othmer Encyclopedia of Chemical Technology. New York, John Wiley and Sons,
Inc. 1969.
3. Fluidized Recovery System Nabs Carbon Disulfide. Chem. Eng. 70(8):92-94. April 15, 1963.
4. Private communication between Resources Research, Incorporated, and Rayon Manufacturing Plant.
December 1969.
5. Private communication between Resources Research, Incorporated, and E.I. Dupont de Nemours and
Company. January 13, 1970.
5.19-2 EMISSION FACTORS 2/72
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5.20 SYNTHETIC RUBBER
5.20.1 Process Descriptionl
Copolymers of butadiene and styrene, commonly known as SBR, account for more than 70 percent of all
synthetic rubber produced in the United States. In a typical SBR manufacturing process, the monomers of
butadiene and styrene are mixed with additives such as soaps and mercaptans. The mixture is polymerized to a
conversion point of approximately 60 percent. After being mixed with various ingredients such as oil and carbon
black, the latex product is coagulated and precipitated from the latex emulsion. The rubber particles are then
dried and baled.
5.20.2 Emissions and Controls1
Emissions from the synthetic rubber manufacturing process consist of organic compounds (largely the
monomers used) emitted from the reactor and blow-down tanks, and particulate matter and odors from the
drying operations.
Drying operations are frequently controlled with fabric filter systems to recover any particulate emissions,
which represent a product loss. Potential gaseous emissions are largely controlled by recycling the gas stream back
to the process. Emission factors from synthetic rubber plants are summarized in Table 5.20-1.
Table 5.20-1. EMISSION FACTORS FOR
SYNTHETIC RUBBER PLANTS: BUTADIENE-
ACRYLONITRILE AND BUTADIENE-STYRENE
EMISSION FACTOR RATING: E
Compound
Alkenes
Butadiene
Methyl propene
Butyne
Pentadiene
Alkanes
Dime thy Iheptane
Pentane
Ethanenitrile
Carbonyls
Acrylonitrile
Acrolein
Emissions3'13
Ib/ton
40
15
3
1
1
2
1
17
3
kg/MT
20
7.5
1.5
0.5
0.5
1
0.5
8.5
1.5
aThe butadiene emission is not continuous and is
greatest right after a batch of partially polymerized
latex enters the blow-down tank.
bReferences 2 and 3.
2/72
Chemical Process Industry
5.20-1
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References for Section 5.20
1. Air Pollutant Emission Factors. Final Report. Resources Research Inc. Reston, Va. Prepared for National Air
Pollution Control Administration. Durham. N.C., under Contract Number CF'A-22-69-119. April 1970.
2. The Louisville Air Pollution Study. U.S. DHEW, PHS, Division of Air Pollution. Cincinnati, Ohio. 1961. p.
26-27 and 124.
3. Unpublished data from synthetic rubber plant. U.S. DHEW, PHS, EHS, National Air Pollution Control
Administration, Division of Air Quality and Emissions Data. Durham, N.C. 1969.
5.20-2 EMISSION FACTORS 2/72
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5.21 TEREPHTHALIC ACID
5.21.1 Process Description1'2
The main use of terephthalic acid is to produce dimethylterephthalate, which is used for polyester fibers (like
Dacron) and films. Terephthalic acid can be produced in various ways, one of which is the oxidation of/J-xylene
by nitric acid. In this process an oxygen-containing gas (usually air), p-xylene, and HN03 are all passed into a
reactor where oxidation by the nitric acid takes place in two steps. The first step yields primarily ^O; the second
step yields mostly NO in the offgas. The terephthalic acid precipitated from the reactor effluent is recovered by
conventional crystallization, separation, and drying operations.
5.21.2 Emissions
The NO in the offgas from the reactor is the major air contaminant from the manufacture of terephthalic acid.
The amount of nitrogen oxides emitted is roughly estimated in Table 5.21-1.
Table 5.21-1. NITROGEN OXIDES
EMISSION FACTORS FOR
TEREPHTHALIC ACID PLANTS3
EMISSION FACTOR RATING: D
Type of operation
Reactor
Nitrogen oxides
(NO)
Ib/ton
13
kg/MT
65
aReference 2.
References for Section 5.21
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C. under Contract Number CPA-22-69-119. April 1970.
2. Terephthalic Acid. In. Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 9. New York, John Wiley
and Sons, Inc. 1964.
2/72 Chemical Process Industry 5.21-1
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6. FOOD AND AGRICULTURAL INDUSTRY
Before food and agricultural products are used by the consumer they undergo a number of processing steps,
such as refinement, preservation, and product improvement, as well as storage and handling, packaging, and
shipping. This section deals with the processing of food and agricultural products and the intermediate steps that
present air pollution problems. Emission factors are presented for industries where data were available. The
primary pollutant emitted from these processes is particulate matter.
6.1 ALFALFA DEHYDRATING by Tom Lahre
6.1.1 General13
Dehydrated alfalfa is a meal product resulting from the rapid drying of alfalfa by artifical means at
temperatures above 212°F (100°C). Alfalfa meal is used in chicken rations, cattle feed, hog rations, sheep feed,
turkey mash, and other formula feeds. It is important for its protein content, growth and reproductive factors,
pigmenting xanthophylls, and vitamin contributions.
A schematic of a generalized alfalfa dehydrator plant is given in Figure 6.1-1. Standing alfalfa is mowed and
chopped in the field and transported by truck to a dehydrating plant, which is usually located within 10 miles of
the field. The truck dumps the chopped alfalfa (wet chops) onto a self-feeder, which carries it into a direct-fired,
rotary drum. Within the drum, the wet chops are dried from an initial moisture content of about 60 to 80 percent
(by weight) to about 8 to 16 percent. Typical combustion gas temperatures within the oil- or gas-fired drums
range from 1800 to 2000°F (980 to 1092°C) at the inlet to 250 to 300°F (120 to 150°C) at the outlet.
From the drying drum, the dry chops are pneumatically conveyed into a primary cyclone that separates them
from the high-moisture, high-temperature exhaust stream. From the primary cyclone, the chops are fed into a
hammermill, which grinds the dry chops into a meal. The meal is pneumatically conveyed from the hammermill
into a meal collector cyclone in which the meal is separated from the airstream and discharged into a holding bin.
Meal is then fed into a pellet mill where it is steam conditioned and extruded into pellets.
From the pellet mill, the pellets are either pneumatically or mechanically conveyed to a cooler, through which
air is drawn to cool the pellets and, in some cases, remove fines. Fines removal is more commonly effected in
shaker screens following or ahead of the cooler, with the fines being conveyed back into the meal collector
cyclone, meal bin, or pellet mill. Cyclone separators may be employed to separate entrained fines in the cooler
exhaust and to collect pellets when the pellets are pneumatically conveyed from the pellet mill to the cooler.
Following cooling and screening, the pellets are transferred to bulk storage. Dehydrated alfalfa is most often
stored and shipped in pellet form; however, in some instances, the pellets may be ground in a hammermill and
shipped in meal form. When the finished pellets or ground pellets are pneumatically transferred to storage or
loadout, additional cyclones may be employed for product airstream separation at these locations.
6.1.2 Emissions and Controls*"3
Particulate matter is the primary pollutant of concern from alfalfa dehydrating plants although some odors
arise from the organic volatiles driven off during drying. Although the major source is the primary cooling
cyclone, lesser sources include the downstream cyclone separators and the bagging and loading operations.
4/76 6.1-1
-------
Emission factors for the various cyclone separators utilized in alfalfa dehydrating plants are given in Table
6.1-1. Note that, although these sources are common to many plants, there will be considerable variation from
the generalized flow diagram in Figure 6.1-1 depending on the desired nature of the product, the physical layout
of the plant, and the modifications made for air pollution control. Common variations include ducting the
exhaust gas stream from one or more of the downstream cyclones back through the primary cyclone and ducting
a portion of the primary cyclone exhaust back into the furnace. Another modification involves ducting a part of
the meal collector cyclone exhaust back into the hammermill, with the remainder ducted to the primary cyclone
or discharged directly to the atmosphere. Also, additional cyclones may be employed if the pellets are
pneumatically rather than mechanically conveyed from the pellet mill to the cooler or if the finished pellets or
ground pellets are pneumatically conveyed to storage or loadout.
Table 6.1-1. PARTICULATE EMISSION FACTORS FOR ALFALFA DEHYDRATING PLANTS
EMISSION FACTOR RATING: PRIMARY CYCLONES: A
ALL OTHER SOURCES: C
Sources3
Primary cyclone
Meal collector cyclone^
Pellet collector cyclone6
Pellet cooler cyclone'
Pellet regrind cycloneS
Storage bin cyclone'1
Emissions
Ib/ton of product"3
10C
2.6
Not available
3
8
Neg.
kg/MT of product'3
5C
1.3
Not available
1.5
4
Neg.
aThe cyclones used for product/airstream separation are the air pollution sources in alfalfa dehydrating plants.
All factors are based on References 1 and 2.
Product consists of meal or pellets. These factors can be applied to the quantity of incoming wet chops by
dividing by a factor of four.
cThis average factor may be used even when other cyclone exhaust streams are ducted back into the primary
cyclone. Emissions from primary cyclones may range from 3 to 35 Ib/ton (1.5 to 17.5 kg/MT) of product
and are more a function of the operating procedures and process modifications made for air pollution control
than whether other cyclone exhausts are ducted back through the primary cyclone. Use 3 to 15 Ib/ton (1.5 to
7.5 kg/MT) for plants employing good operating procedures and process modifications for air pollution control.
Use higher values for older, unmodified, or less well run plants.
This cyclone is also called the air meal separator or hammermill cyclone. When the meal collector exhaust is
ducted back to the primary cyclone and/or the hammermill, this cyclone is no longer a source,
^his cyclone will only be present if the pellets are pneumatically transferred from the P'ellet mill to the pellet
cooler.
This cyclone is also called the pellet meal air separator or pellet mill cyclone. When the pellet cooler cyclone
exhaust is ducted back into the primary cyclone, it is no longer a source.
^This cyclone is also called the pellet regrind air separator. Regrind operations are more commonly found at
terminal storage facilities than at dehydrating plants.
Small cyclone collectors may be used to collect the finished pellets when they are pneumatically transferred
to storage.
Air pollution control (and product recovery) is accomplished in alfalfa dehyarating plants in a variety of ways.
A simple, yet effective technique is the proper maintenance and operation of the alfalfa dehydrating equipment.
Particulate emissions can be reduced significantly if the feeder discharge rates are uniform, if the dryer furnace is
operated properly, if proper airflows are employed in the cyclone collectors, and if the hammermill is well
maintained and not overloaded. It is especially important in this regard not to overdry and possibly burn the
chops as this results in the generation of smoke and increased fines in the grinding and pelletizing operations.
6.1-2
EMISSION FACTORS
4/76
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c
co
c
o
CD
•a
42
CO
_
O
4—
-a
OJ
N
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C
a>
CD
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4/76
Food and Agricultural Industry
6.1-3
-------
Equipment modification provides another means of particulate control. Existing cyclones can be replaced with
more efficient cyclones and concomitant air flow systems. In addition, the furnace and burners can be modified
or replaced to minimize flame impingement on the incoming green chops. In plants where the hammermill is a
production bottleneck, a tendency exists to overdry the chops to increase throughput, which results in increased
emissions. Adequate hammermill capacity can reduce this practice.
Secondary control devices can be employed on the cyclone collector exhaust streams. Generally, this practice
has been limited to the installation of secondary cyclones or fabric filters on the meal collector, pellet collector,
or pellet cooler cyclones. Some measure of secondary control can also be effected on these cyclones by ducting
their exhaust streams back into the primary cyclone. Primary cyclones are not controlled by fabric filters because
of the high moisture content in the resulting exhaust stream. Medium energy wet scrubbers are effective in
reducing particulate emissions from the primary cyclones, but have only been installed al a few plants.
Some plants employ cyclone effluent recycle systems for particulate control. One system skims off the
particulate-laden portion of the primary cyclone exhaust and returns it to the furnace for incineration. Another
system recycles a large portion of the meal collector cyclone exhaust back to the hammermill. Both systems can
be effective in controlling particulates but may result in operating problems, such as condensation in the recycle
lines and plugging or overheating of the hammermill.
References for Section 6.1
1. Source information supplied by Ken Smith of the American Dehydrators Association, Mission, Kan.
December 1975.
2. Gorman, P.G. et al. Emission Factor Development for the Feed and Grain Industry. Midwest Research
Institute. Kansas City, Mo. Prepared for Environmental Protection Agency, Research Triangle Park, N.C.
under Contract No. 68-02-1324. Publication No. EPA450/3-75-054. October 1974.
3. Smith, K.D. Particulate Emissions from Alfalfa Dehydrating Plants - Control Costs and Effectiveness. Final
Report. American Dehydrators Association. Mission, Kan. Prepared for Environmental Protection Agency,
Research Triangle Park, N.C. Grant No. R801446. Publication No. 650/2-74-007. January 1974.
6.1-4 EMISSION FACTORS 4/76
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6.2 COFFEE ROASTING
6.2.1 Process Descriptionl >2
Coffee, which is imported in the form of green beans, must be cleaned, blended, roasted, and packaged before
being sold. In a typical coffee roasting operation, the green coffee beans are freed of dust and chaff by dropping
the beans into a current of air. The cleaned beans are then sent to a batch or continuous roaster. During the
roasting, moisture is driven off, the beans swell, and chemical changes take place that give the roasted beans their
typical color and aroma. When the beans have reached a certain color, they are quenched, cooled, and stoned.
6.2.2 Emissions1'2
Dust, chaff, coffee bean oils (as mists), smoke, and odors are the principal air contaminants emitted from
coffee processing. The major source of particulate emissions and practically the only source of aldehydes,
nitrogen oxides, and organic acids is the roasting process. In a direct-fired roaster, gases are vented without
recirculation through the flame. In the indirect-fired roaster, however, a portion of the roaster gases are
recirculated and particulate emissions are reduced. Emissions of both smoke and odors from the roasters can be
almost completely removed by a properly designed afterburner.1 >2
Particulate emissions also occur from the stoner and cooler. In the stoner, contaminating materials heavier
than the roasted beans are separated from the beans by an air stream. In the cooler, quenching the hot roasted
beans with water causes emissions of large quantities of steam and some particulate matter.3 Table 6.2-1
summarizes emissions from the various operations involved in coffee processing.
Table 6.2-1. EMISSION FACTORS FOR ROASTING PROCESSES WITHOUT CONTROLS
EMISSION FACTOR RATING: B
Type of process
Roaster
Direct-fired
Indirect-fired
Stoner and cooler0
Instant coffee spray dryer
Pollutant
Particulates8
Ib/ton
7.6
4.2
1.4
1.4d
kg/MT
3.8
2.1
0.7
0.7d
N0xb
Ib/ton
0.1
0.1
_
-
kg/MT
0.05
0.05
_
-
Aldehydes6
Ib/ton
0.2
0.2
—
-
kg/MT
0.1
0.1
_
-
Organic acidsb
Ib/ton
0.9
0.9
—
-
kg/MT
0.45
0.45
_
-
aReference 3.
"Reference 1.
clf cyclone is used, emissions can be reduced by 70 percent.
"Cyclone plus wet scrubber always used, representing a controlled factor
2/72
Food and Agricultural Industry
6.2-1
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References for Section 6.2
1. Polglase, W.L., H.F. Dey, and R.T. Walsh. Coffee Processing. In: Air Pollution Engineering Manual.
Danielson, J.A. (ed.). U.S. DHEW, PHS, National Center for Air Pollution Control. Cincinnati, Ohio.
Publication Number 999-AP-40. 1967. p. 746-749.
2. Duprey, R.L. Compilation of Air Pollutant Emission Factors. U.S. DHEW, PHS, National Center for Air
Pollution Control. Durham, N.C. PHS Publication Number 999-AP-42. 1968. p. 19-20.
3. Partee, F. Air Pollution in the Coffee Roasting Industry. Revised Ed. U.S. DHEW, PHS, Division of Air
Pollution. Cincinnati, Ohio. Publication Number 999-AP-9. 1966.
6.2-2 EMISSION FACTORS 2/72
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6.3 COTTON GINNING
6.3.1 General1
The primary function of a cotton gin is to take raw seed cotton and separate the seed and the lint. A large
amount of trash is found in the seed cotton, and it must also be removed. The problem of collecting and
disposing of gin trash is two-fold. The first problem consists of collecting the coarse, heavier trash such as burrs,
sticks, stems, leaves, sand, and dirt. The second problem consists of collecting the finer dust, small leaf particles,
and fly lint that are discharged from the lint after the fibers are removed from the seed. From 1 ton (0.907 MT)
of seed cotton, approximately one 500-pound (226-kilogram) bale of cotton can be made.
6.3.2 Emissions and Controls
The major sources of particulates from cotton ginning include the unloading fan, the cleaner, and the stick and
burr machine. From the cleaner and stick and burr machine, a large percentage of the particles settle out in the
plant, and an attempt has been made in Table 6.3-1 to present emission factors that take this into consideration.
Where cyclone collectors are used, emissions have been reported to be about 90 percent less.1
Table 6.3-1. EMISSION FACTORS FOR COTTON GINNING OPERATIONS
WITHOUT CONTROLS8'5
EMISSION FACTOR RATING: C ''
Process
Unloading fan
Cleaner
Stick and burr
machine
Miscellaneous
Total
Estimated total
particulates
Ib/bale
5
1
3
3
12
kg/bale
2.27
0.45
1.36
1.36
5.44
Particles > 100jum
settled out, %
0
70
95
50
—
Estimated
emission factor
(released to
atmosphere)
Ib/bale
5.0
0.30
0.20
1.5
7.0
kg/bale
2.27
0.14
0.09
0.68
3.2
References 1 and 2.
One bale weighs 500 pounds (226 kilograms).
References for Section 6.3
1. Air-Borne Particulate Emissions from Cotton Ginning Operations. U.S. DHEW, PHS, Tail Sanitary
Engineering Center. Cincinnati, Ohio. 1960.
2. Control and Disposal of Cotton Ginning Wastes. A Symposium Sponsored by National Center for Air
Pollution Control and Agricultural Research Service, Dallas, Texas. May 1966.
2/72
Food and Agricultural Industry
6.3-1
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6.4 FEED AND GRAIN MILLS AND ELEVATORS
6.4.1 General1"3
Grain elevators are buildings in which grains are gathered, stored, and discharged for use, further
processing, or shipping. They are classified as "country," "terminal," and "export" elevators, according
to their purpose and location. At country elevators, grains are unloaded, weighed, and placed in
storage as they are received from farmers residing within about a 20-mile radius of the elevator. In
addition, country elevators sometimes dry or clean grain before it is shipped to terminal elevators or
processors.
Terminal elevators receive most of their grain from country elevators and ship to processors, other
terminals, and exporters. The primary functions of terminal elevators are to store large quantities of
grain without deterioration and to dry, clean, sort, and blend different grades of grain to meet buyer
specifications.
Export elevators are similar to terminal elevators except that they mainly load grain on ships for
export.
Processing of grain in mills and feed plants ranges from very simple mixing steps to complex
industrial processes. Included are such diverse processes as: (1) simple mixing operations in feed mills,
(2) grain milling in flour mills, (3) solvent extracting in soybean processing plants, and (4) a complex
series of processing steps in a corn wet-milling plant.
6.4.2 Emissions and Controls
Grain handling, milling, and processing include a variety of operations from the initial receipt of
the grain at either a country or terminal elevator to the delivery of a finished product. Flour, livestock
feed, soybean oil, and corn syrup are among the products produced from plants in the grain and feed
industry. Emissions from the feed and grain industry can be separated into two general areas, those
occurring at grain elevators and those occurring at grain processing operations.
6.4.2.1 Grain Elevators - Grain elevator emissions can occur from many different operations in the
elevator including unloading (receiving), loading (shipping), drying, cleaning, headhouse (legs),
tunnel belt, gallery belt, and belt trippers. Emission factors for these operations at terminal, country,
and export elevators are presented in Table 6.4-1. All of these emission factors are approximate average
values intended to reflect a variety of grain types. Actual emission factors for a specific source may be
considerably different, depending on the type of grain, i.e., corn, soybeans, wheat, and other factors
such as grain quality.
The emission factors shown in Table 6.4-1 represent the amount of dust generated per ton of grain
processed through each of the designated operations (i.e., uncontrolled emission factors). Amounts of
grain processed through each of these operations in a given elevator are dependent on such factors as
the amount of grain turned (interbin transfer), amount dryed, and amount cleaned, etc. Because the
amount of grain passing through each operation is often difficult to determine, it may be more useful
to express the emission factors in terms of the amount of grain shipped or received, assuming these
amounts are about the same over the long term. Emission factors from Table 6.4-1 have been modified
accordingly and are shown in Table 6.4-2 along with the appropriate multiplier that was used as repre-
sentative of typical ratios of throughput at each operation to the amount of grain shipped or received.
This ratio is an approximate value based on average values for turning, cleaning, and drying in each
4/77 Food and Agricultural Industry 6.4-1
-------
type of elevator. However, because operating practices in individual elevators are different, these
ratios, like the basic emission factors themselves, are more valid when applied to a group of elevators
rather than individual elevators.
Table 6.4-1. PARTICULATE EMISSION FACTORS
FOR UNCONTROLLED GRAIN ELEVATORS
EMISSION FACTOR RATING: B
Type of source
Terminal elevators
Unloaded (receiving)
Loading (shipping)
Removal from bins (tunnel belt)
Drying'3
Cleaning0
Headhouse (legs)
Tripper (gallery belt)
Country elevators
Unloading (receiving)
Loading (shipping)
Removal from bins
Drying13
Cleaning0
Headhouse (legs)
Export elevators
Unloading (receiving)
Loading (shipping)
Removal from bins (tunnel belt)
Drying"
Cleaning0
Headhouse (legs)
Tripper (gallery belts)
Emission factor3
Ib/ton
1.0
0.3
1.4
1.1
3.0
1.5
1.0
0.6
0.3
1.0
0.7
3.0
1.5
1.0
1.0
1.4
1.1
3.0
1.5
1.0
kg/MT
0.5
0.2
1.7
0.6
1.5
0.8
0.5
0.3
0.2
0.5
0.4
1.5
0.8
0.5
0.5
0.7
0.5
1.5
0.8
0.5
aEmission factors are in terms of pounds of dust emitted per ton of
grain processed by each operation. Most of the factors for terminal
and export elevators are based on Reference 1. Emission factors
for drying are based on References 2 and 3. The emission factors
for country elevators are based on Reference 1 and specific country
elevator test data in References 4 through 9.
Emission factors for drying are based on 1.8 Ib/ton for rack dryets
and 0.3 Ib/ton for column dryers prorated on the basis of distribu-
tion of these two types of dryers in each elevator category, as
discussed in Reference 3.
cEmission factor of 3.0 for cleaning is an average value which may
range from <0.5 for wheat up to 6.0 for corn.
The factors in Tables 6.4-1 or 6.4-2 should not be added together in an attempt to obtain a single
emission factor value for grain elevators because in most elevators some of the operations are
equipped with control devices and some are not. Therefore, any estimation of emissions must be
directed to each operation and its associated control device, rather than the elevator as a whole, unless
the purpose was to estimate total potential (i.e., uncontrolled) emissions. An example of the use of
emission factors in making an emission inventory is contained in Reference 3.
6.4-2
EMISSION FACTORS
4/77
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Table 6.4-2. PARTICULATE EMISSION FACTORS FOR GRAIN ELEVATORS BASED ON
AMOUNT OF GRAIN RECEIVED OR SHIPPED9
Type of source
Terminal elevators
Unloading (receiving)
Loading (shipping)
Removal from bins (tunnel belt)
Drying"
Cleaning0
Headhouse (legs)
Tripper (gallery belt)
Country elevators
Unloading (receiving)
Loading (shipping)
Removal from bins
Drymgb
Cleaning0
Headhouse (legs)
Export elevators
Unloading (receiving)
Loading (shipping)
Removal from bins (tunnel belt)
Drymgb
Cleanmg0
Headhouse (legs)
Tripper (gallery belt)
Emission factor,
Ib/ton processed
1.0
0.3
1.4
1.1
3.0
1 5
1 0
0.6
0.3
1.0
0.7
30
1 5
1.0
1.0
1.4
1.1
3.0
1.5
1.0
X
Typical ratio of tons processed
to tons received or shipped"
1.0
1.0
2.0
0.1
0.2
3.0
1.7
1.0
1.0
2.1
0.3
0.1
3.1
1.0
1.0
1.2
0.01
0.2
2 2
1 1
=
Emission factor,
Ib/ton received or shipped
1.0
03
2.8
0.1
0.6
4.5
1.7
0.6
03
2 1
02
0.3
4.7
1 0
1 0
1.7
0.01
0.6
33
1 1
aAssume that over the long term the amount received is approximately equal to amount shipped.
bSeeNoteb in Table 6.4-1.
ICSee Notec in Table 6.4-1. I
"Ratios shown are average values taken from a survey of many elevators across the U.S. These ratios can be considerably different
for any individual elevator or group of elevators in the same locale.
Some of the operations listed in the table, such as the tunnel belt and belt tripper, are internal or
in-house dust sources which, if uncontrolled, might show lower than expected atmospheric emissions
because of internal settling of dust. The reduction in emissions via internal settling is not known,
although it is possible that all of this dust is eventually emitted to the atmosphere due to subsequent
external operations, internal ventilation, or other means.
Many elevators utilize control devices on at least some operations. In the past, cyclones have com-
monly been applied to legs in the headhouse and tunnel belt hooding systems. More recently, fabric
filters have been utilized at many elevators on almost all types of operations. Unfortunately, some
sources in grain elevators present control problems. Control of loadout operations is difficult because
of the problem of containment of the emissions. Probably the most difficult operation to control,
because of the large flow rate and high moisture content of the exhaust gases, is the dryers. Screen-
houses or continuously vacuumed screen systems are available for reducing dryer emissions and have
been applied at several facilities. Detailed descriptions of dust control systems for grain elevator oper-
ations are contained in Reference 2.
6.4.2.2 Grain Processing Operations - Grain processing operations include many of the operations
performed in a grain elevator in addition to milling and processing of the grain. Emission factors for
different grain milling and processing operations are presented in Table 6.4-3. Brief discussions of
these different operations and the methods used for arriving at the emission factor values shown in
Table 6.4-3 are presented below.
4/77
Food and Agricultural Industry
6.4-3
-------
Table 6.4-3. PARTICULATE EMISSION FACTORS
FOR GRAIN PROCESSING OPERATIONSl.2,3
EMISSION FACTOR RATING: 0
Type of source
Feed mills
Receiving
Shipping
Handling
Grinding
Pellet coolers
Wheat mills
Receiving
Precleaning and handling
Cleaning house
Millhouse
Durum mills
Receiving
Precleaning and handling
Cleaning house
Millhouse
Rye milling
Receiving
Precleaning and handling
Cleaning house
Millhouse
Dry corn milling
Receiving
Drying
Precleaning and handling
Cleaning house
Degerming and milling
Oat milling
Total
Rice milling
Receiving
Handling and precleaning
Drying
Cleaning and millhouse
Soybean mills
Receiving
Handling
Cleaning
Drying
Cracking and denuding
Hull grinding
Emission factora.b
(uncontrolled except where indicated)
Ib/ton
1.30
0.50
3.00
0.1 QC
0.1 QC
1.00
5.00
-
70.00
1.00
5.00
-
-
1.00
5.00
-
70.00
1.00
0.50
5.00
6.00
-
2.5Qd
0.64
5.00
1.60
5.00
-
7.20
3.30
2.00
kg/MT
0.65
0.25
1.50
0.05C
0.05C
0.50
2.50
-
35.00
0.50
2.50
-
-
0.50
2.50
-
35.00
0.50
0.25
2.50
3.00
-
1.25d
0.32
2.50
0.80
2.50
-
3.60
1.65
1.00
6.4-4
EMISSION FACTORS
4/77
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Table 6.4-3 (continued). PA'RTICULATE EMISSION FACTORS
FOR GRAIN PROCESSING OPERATIONS1.2.3
EMISSION FACTOR RATING: D
Type of source
Bean conditioning
Flaking
Meal dryer
Meal cooler
Bulk loading
Corn wet milling
Receiving
Handling
Cleaning
Dryers
Bulk loading
Emission factora-b
(uncontrolled except where indicated)
Ib/ton
0.10
0.57
1.50
1.80
0.27
1.00
5.00
6.00
-
-
kg/MT
0.05
0.29
0.75
0.90
0.14
0.50
2.50
3.00
-
-
aEmission factors are expressed in terms of pounds of dust emitted per ton of grain
entering the plant (i.e., received), which is not necessarily the same as the amount
of material processed by each operation.
Blanks indicate insufficient information.
cControlled emission factor (controlled with cyclones).
"Controlled emission factor.lThis represents several sources in one plant; some
controlled with cyclones and others controlled with fabric filters.)
Emission factor data for feed mill operations are sparse. This is partly due to the fact that many
ingredients, whole grain and other dusty materials (bran, dehydrated alfalfa, etc.), are received by
both truck and rail and several unloading methods are employed. However, because some feed mill
operations (handling, shipping, and receiving) are similar to operations in a grain elevator, an emis-
sion factor for each of these different operations was estimated on that basis. The remaining
operations are based on information in Reference 2.
Three emission areas for wheat mill processing operations are grain receiving and handling, clean-
ing house, and milling operations. Data from Reference 1 are used to estimate emissions factors for
grain receiving and handling. Data for the cleaning house are insufficient to estimate an emission
factor, and information contained in Reference 2 is used to estimate the emission factor for milling
operations. The large emission factor for the milling operation is somewhat misleading because almost
all of the sources involved are equipped with control devices to prevent product losses; fabric filters
are widely used for this purpose.
Operations for durum mills and rye milling are similar to those of wheat milling. Therefore, most
of these emission factors are assumed equal to those for wheat mill operations.
The grain unloading, handling, and cleaning operations for dry corn milling are similar to those in
other grain mills, but the subsequent operations are somewhat different. Also, some drying of corn
received at the mill may be necessary prior to storage. An estimate of the emission factor for drying is
obtained from Reference 2. Insufficient information is available to estimate emission factors for
degerming and milling.
Information necessary to estimate emissions from oat milling is unavailable, and no emission
factor for another grain is considered applicable because oats are reported to be dustier than many,
other grains. The only emission factor data available are for controlled emissions.2 An overall con-
trolled emission factor of 2.5 Ib/ton is calculated from these data.
4/77
Food and Agricultural Industry
6.4-5
-------
Emission factors for rice milling are based on those for similar operations in other grain handling
facilities. Insufficient information is available to estimate emission factors for drying, cleaning, and
mill house operations.
Information contained in Reference 2 is used to estimate emission factors for soybean mills.
Emissions information on corn wet-milling is unavailable in most cases due to the wide variety of
products and the diversity of operations. Receiving, handling, and cleaning operations emission
factors are assumed to be similar to those for dry corn milling.
Many of the operations performed in grain milling and processing plants are the same as those in
grain elevators, so the control methods are similar. As in the case of grain elevators, these plants often
use cyclones or fabric filters to control emissions from the grain handling operations (e.g:, unloading,
legs, cleaners, etc.). These same devices are also often used to control emissions from other processing
operations; a good example of this is the extensive use of fabric filters in flour mills. However, there are
also certain operations within some milling operations that are not amenable to use of these devices.
Therefore, wet scrubbers have found some application, particularly where the effluent gas stream has
a high moisture content. Certain other operations have been found to be especially difficult to control,
such as rotary dryers in wet corn mills. Descriptions of the emission control systems that have been
applied to operations within the grain milling and processing industries are contained in Reference 2.
This section was prepared for EPA by Midwest Research Institute.10
References for Section 6.4
1. Gorman, P.G. Potential Dust Emission from a Grain Elevator in Kansas City, Missouri. Prepared
by Midwest Research Institute for Environmental Protection Agency, Research Triangle Park,
N.C. under Contract No. 68-02-0228, Task Order No. 24. May 1974.
2. Shannon, L.J. et al. Emission Control in the Grain and Feed Industry , Volume I - Engineering
and Cost Study. Final Report. Prepared for Environmental Protection Agency by Midwest
Research Institute. Document No. EPA-450/3-73-003a. Research Triangle Park, N.C. December
1973.
3. Shannon, L.J. et al. Emission Control in the Grain and Feed Industry, Volume II - Emission
Inventory. Final Report. Prepared by Midwest Research Institute for Environmental Protection
Agency, Research Triangle Park, N.C. Report No. EPA-450/3-73-003b. September 1974
4. Maxwell, W.H. Stationary Source Testing of a Country Grain Elevator at Overbrook, Kansas.
Prepared by Midwest Research Institute for Environmental Protection Agency under EPA
Contract No. 68-02-1403. Research Triangle Park, N.C. February 1976.
5. Maxwell, W.H. Stationary Source Testing of a Country Grain Elevator at Great Bend, Kansas.
Prepared by Midwest Research Institute for Environmental Protection Agency under EPA
Contract No. 68-02-1403. Research Triangle Park, N.C. April 1976.
6. Belgea, F.J. Cyclone Emissions and Efficiency Evaluation. Report submitted to North Dakota
State Department of Health on tests at an elevator in Edenburg, North Dakota, by Pollution
Curbs, Inc. St. Paul, Minnesota. March 10, 1972.
7. Trowbridge, A.L. Particulate Emission Testing - ERG Report No. 4-7683. Report submitted to
North Dakota State Department of Health on tests at an elevator in Egeland, North Dakota, by
Environmental Research Corporation. St. Paul, Minnesota. January 16, 1976.
6.4-6 EMISSION FACTORS 4/77
-------
8. Belgea, F. J. Grain Handling Dust Collection Systems Evaluation for Farmers Elevator Company,
Minot, North Dakota. Report submitted to North Dakota State Department of Health, by
Pollution Curbs, Inc. St. Paul, Minnesota. August 28, 1972.
9. Belgea, F.J. Cyclone Emission and Efficiency Evaluation. Report submitted to North Dakota
State Department of Health on tests at an elevator in Thompson, North Dakota, by Pollution
Curbs, Inc. St. Paul, Minnesota. March 10, 1972.
10. Schrag, M.P. et al. Source Test Evaluation for Feed and Grain Industry. Prepared by Midwest
Research Institute, Kansas City, Mo., for Environmental Protection Agency, Research Triangle
Park, N.C., under Contract No. 68-02-1403, Task Order No. 28. December 1976. Publication No.
EPA-450/3-76-043.
4/77 Food and Agricultural Industry 6.4-7
-------
-------
6.5 FERMENTATION
6.5.1 Process Description1
For the purpose of this report only the fermentation industries associated with food will be considered. This
includes the production of beer, whiskey, and wine.
The manufacturing process for each of these is similar. The four main brewing production stages and their
respective sub-stages are: (1) brewhouse operations, which include (a) malting of the barley, (b) addition of
adjuncts (corn, grits, and rice) to barley mash, (c) conversion of starch in barley and adjuncts to maltose sugar by
enzymatic processes, (d) separation of wort from grain by straining, and (e) hopping and boiling of the wort; (2)
fermentation, which includes (a) cooling of the wort, (b) additional yeast cultures, (c) fermentation for 7 to 10
days, (d) removal of settled yeast, and (e) filtration and carbonation; (3) aging, which lasts from 1 to 2 months
under refrigeration; and (4) packaging, which includes (a) bottling-pasteurization, and (b) racking draft beer.
The major differences between beer production and whiskey production are the purification and distillation
necessary to obtain distilled liquors and the longer period of aging. The primary difference between wine making
and beer making is that grapes are used as the initial raw material in wine rather than grains.
6.5.2 Emissions1
Emissions from fermentation processes are nearly all gases and primarily consist of carbon dioxide, hydrogen,
oxygen, and water vapor, none of which present an air pollution problem. Emissions of particulates, however, can
occur in the handling of the grain for the manufacture of beer and whiskey. Gaseous hydrocarbons are also
emitted from the drying of spent grains and yeast in beer and from the whiskey-aging warehouses. No significant
emissions have been reported for the production of wine. Emission factors for the various operations associated
with beer, wine, and whiskey production are shown in Table 6.5-1.
2/72 Food and Agricultural Industry 6.5-1
-------
Table 6.5-1. EMISSION FACTORS FOR FERMENTATION PROCESSES
EMISSION FACTOR RATING: E
Type of product
Beer
Grain handling3
Drying spent grains, etc.3
Whiskey
Grain handling8
Drying spent grains, etc.3
Aging
Wine
Particulates
Ib/ton
3
5
3
5
-
Nege
kg/MT
1.5
2.5
1.5
2.5
-
Neg
Hydrocarbons
Ib/ton
—
NAb
-
NA
10°
Nege
kg/MT
—
NA
-
NA
0.024d
Neg
3Based on section on grain processing.
bNo emission factor available, but emissions do occur.
cPounds per year per barrel of whiskey stored.
"Kilograms per year per liter of whiskey stored.
eNo significant emissions.
References for Section 6.5
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA.-22-69-119. April 1970.
2. Shreve, R.N. Chemical Process Industries, 3rd Ed. New York, McGraw-Hill Book Company. 1967. p.
591-608.
6.5-2
EMISSION FACTORS
2/72
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6.6 FISH PROCESSING revised by Susan Sercer
6.6.1 Process Description
Fish processing includes the canning of fish and the manufacturing of by-products such as fish'oil
and fish meal. The manufacturing of fish oil and fish meal are known as reduction processes. A general-
ized fish processing operation is presented in Figure 6.6-1 .
Two types of canning operations are used. One is the "wet fish" method in which trimmed and
eviscerated fish are cooked directly in open cans. The other operation is the "pre-cooked" process in
which eviscerated fish are cooked whole and portions are hand selected and packed into cans. The pre-
cooked process is used primarily for larger fish such as tuna.
By-product manufacture of rejected whole fish and scrap requires several steps. First, the fish scrap
mixture from the canning line is charged to a live steam cooker. After the material leaves the cooker,
it is pressed to remove water and oil. The resulting press cake is broken up and dried in a rotary drier.
Two types of driers are used to dry the press cake: direct-fired and steam-tube driers. Direct-fired
driers contain a stationary firebox ahead of the rotating section. The hot products of combustion from
the firebox are mixed with air and wet meal inside the rotating section of the drier. Exhaust gases are
generally vented to a cyclone separator to recover much of the entrained fish meal product. Steam-
tube driers contain a cylindrical bank of rotating tubes through which hot, pressurized steam is
passed. Heat is indirectly transferred to the meal and the air from the hot tubes. As with direct-fired
driers, the exhaust gases are vented to a cyclone for product recovery.
6.6.2 Emissions and Controls
Although smoke and dust can be a problem, odors are the most objectionable emissions from fish
processing plants. By-product manufacture results in more of these odorous contaminants than
cannery operations because of the greater state of decomposition of the materials processed. In gener-
al, highly decayed feedstocks produce greater concentrations of odors than do fresh feedstocks.
The largest odor sources are the fish meal driers. Usually, direct-fired driers emit more odors than
steam-tube driers. Direct-fired driers will also emit smoke, particularly if the driers are operated
under high temperature conditions. Cyclones are frequently employed on drier exhaust gases for
product recovery and paniculate emission control.
Odorous gases from reduction cookers consist primarily of hydrogen sulfide [H2S] and trimethyl-
amine [(CH3).,N]. Odors from reduction cookers are emitted in volumes appreciably less than from fish
meal driers. There are virtually no particulate emissions from reduction cookers.
Some odors are also produced by the canning processes. Generally, the pre-cooked process emits
less odorous gases than the wet-fish process. This is because in the pre-cooked process, the odorous
exhaust gases are trapped in the cookers, whereas in the wet-fish process, the steam and odorous
offgases are commonly vented directly to the atmosphere.
Fish cannery and fish reduction odors can be controlled with afterburners, chlorinator-scrubbers,
and condensers. Afterburners are most effective, providing virtually 100 percent odor control; how-
ever they are costly from a fuel-use standpoint. Chlbrinator-scrubbers have been found to be 95 to 99
percent effective in controlling odors from cookers and driers. Condensers are the least effective
control device. Generally, centrifugal collectors are satisfactory for controlling excessive dust emis-
sions from driers.
Emission factors for fish processing are presented in Table 6.6-1.
4/77 Food and Agricultural Industry 6.6-1
-------
E
2
05
2
T:
5
05
c
O)
O)
CD
CD
3
LL
6.6-2
EMISSION FACTORS
4/77
-------
Table 6.6-1. EMISSION FACTORS FOR FISH PROCESSING PLANTS
EMISSION FACTOR RATING: C
Emission source
Cookers, canning
Cookers, fish scrap
Fresh fish
Stale fish
Dryers '
Particulates
Ib/ton
Neg.a
Neg.a
Neg.a
0.1 d
kg/MT
Neg.a
Neg.a
Neg.a
0.05d
Trimethylamine
(CH3)3N
Ib/ton
NAb
0.3C
3.5C
NAd
kg/MT
NAb
0.1 5C
1.75C
NAd
Hydrogen sulfide
(H2S)
Ib/ton
NAb
0.01C
0.2°
NAd
kg/MT
NAb
0.005C
0.10°
NAd
aReference 1.
^Although it is known that odors are emitted from canning cookers, quantitative estimates are not available.
"•Reference 2.
"Limited data suggest that there is not much difference in paniculate emissions between steam tube and direct-fired
dryers. Based on reference 1.
References for Section 6.6
1. Walsh, R.T., K.D. Luedtke, and L.K. Smith. Fish Canneries and Fish Reduction Plants. In: Air
Pollution Engineering Manual. Danielson, J.A. (ed.). U.S. DHEW, PHS, National Center for Air
Pollution Control. Cincinnati, Ohio. Publication Number 999-AP-40. 1967. p. 760-770.
2. Summer, W. Methods of Air Deodorization. New York, Elsevier Publishing Company. 1963. p.
284-286.
4/77
Food and Agricultural Industry
6.6-3
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6.7 MEAT SMOKEHOUSES
6.7.1 Process Description1
Smoking is a diffusion process in which food products are exposed to an atmosphere of hardwood smoke,
causing various organic compounds to be absorbed by the food. Smoke is produced commerically in the United
States by three major methods: (1) by burning dampened sawdust (20 to 40 percent moisture), (2) by burning
dry sawdust (5 to 9 percent moisture) continuously, and (3) by friction. Burning dampened sawdust and
kiln-dried sawdust are the most widely used methods. Most large, modern, production meat smokehouses are the
recirculating type, in which smoke is circulated at reasonably high temperatures throughout the smokehouse.
6.7.2 Emissions and Controls1
Emissions from smokehouses are generated from the burning hardwood rather than from the cooked product
itself. Based on approximately 110 pounds of meat smoked per pound of wood burned (110 kilograms of meat
per kilogram of wood burned), emission factors have been derived for meat smoking and are presented in Table
6.7-1.
Emissions from meat smoking are dependent on several factors, including the type of wood, the type of smoke
generator, the moisture content of the wood, the air supply, and the amount of smoke recirculated. Both
low-voltage electrostatic precipitators and direct-fired afterburners may be used to reduce particulate and organic
emissions. These controlled emission factors have also been shown in Table 6.7-1.
Table 6.7-1. EMISSION FACTORS FOR MEAT SMOKINGa-b
EMISSION FACTOR RATING: D
Pollutant
Particulates
Carbon monoxide
Hydrocarbons (CH4)
Aldehydes (HCHO)
Organic acids (acetic)
Uncontrolled
Ib/ton of meat
0.3
0.6
0.07
0.08
0.2
kg/MT of meat
0.15
0.3
0.035
0.04
0.10
Controlled0
Ib/ton of meat
0.1
Negd
Neg
0.05
0.1
kg/MT of meat
0.05
Neg
Neg
0.025
0.05
aBased on 110 pounds of meat smoked per pound of wood burned (110 kg meat/kg wood burned).
^References 2, 3, and section on charcoal production.
cControls consist of either a wet collector and low-voltage precipitator in series or a direct-fired afterburner.
dWith afterburner.
2/72
Food and Agricultural Industry
6.7-1
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References for Section 6.7
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Carter, E. Private communication between Maryland State Department of Health and Resources Research,
Incorporated. November 21, 1969.
3. Polglase, W.L., H.F. Dey, and R.T. Walsh. Smokehouses. In: Air Pollution Engineering Manual. Danielson, J.
A. (ed.). U.S. DHEW, PHS, National Center for Air Pollution Control. Cincinnati, Ohio. Publication Number
999-AP-40. 1967. p. 750-755.
6.7-2 EMISSION FACTORS 2/72
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6.8 NITRATE FERTILIZERS
6.8.1 General1'2
For this report, nitrate fertilizers are defined as the product resulting from the reaction of nitric acid and
ammonia to form ammonium nitrate solutions or granules. Essentially three steps are involved in producing
ammonium nitrate: neutralization, evaporation of the neutralized solution, and control of the particle size and
characteristics of the dry product.
Anhydrous ammonia and nitric acid (57 to 65 percent HNC^)3'4 are brought together in the neutralizer to
produce ammonium nitrate. An evaporator or concentrator is then used to increase the ammonium nitrate
concentration. The resulting solutions may be formed into granules by the use of prilling towers or by ordinary
granulators. Limestone may be added in either process in order to produce calcium ammonium nitrate.5 ^
6.8.2 Emissions and Controls
The main emissions from the manufacture of nitrate fertilizers occur in the neutralization and drying
operations. By keeping the neutralization process on the acidic side, losses of ammonia and nitric oxides are kept
at a minimum. Nitrate dust or particulate matter is produced in the granulation or prilling operation. Particulate
matter is also produced in the drying, cooling, coating, and material handling operations. Additional dust may
escape from the bagging and shipping facilities.
Typical operations do not use collection devices on the prilling tower. Wet or dry cyclones, however, are used
for various granulating, drying, or cooling operations in order to recover valuable products. Table 6.8-1 presents
emission factors for the manufacture of nitrate fertilizers.
2/72 Food and Agricultural Industry 6.8-1
-------
Table 6.8-1. EMISSION FACTORS FOR NITRATE FERTILIZER
MANUFACTURING WITHOUT CONTROLS
EMISSION FACTOR RATING: B
Type of process3
With prilling towerb
Neutralizerc-d
Prilling tower
Dryers and coolers6
With granulatorb
Neutralizerc'd
Granulator6
Dryers and coolers6'*
Particulates
Ib/ton
—
0.9
12
—
0.4
7
kg/MT
—
0.45
6
—
0.2
3.5
Nitrogen
oxides (N03)
Ib/ton
—
-
—
—
0.9
3
kg/MT
—
-
—
—
0.45
1.5
Ammonia
Ib/lon
2
—
—
2
0.5
1.3
kg/MT
1
—
_
1
0.25
0.65
aPlants will use either a prilling tower or a granulator but not both.
'•'Reference 7.
cReference 8.
"Controlled factor based on 95 percent recovery in recycle scrubber.
eUse of wet cyclones can reduce emissions by 70 percent.
Use of wet-screen scrubber following cyclone can reduce emissions by 95 to 97 percent
References for Section 6.8
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA -22-69-119. April 1970.
2. Stem, A. (ed.). Sources of Air Pollution and Their Control. In: Air Pollution Vol. Ill, 2nd Ed. New York,
Academic Press. 1968. p. 231-234.
3. Sauchelli, V. Chemistry and Technology of Fertilizers. New York, Reinhold Publishing Company. 1960.
4. Falck-Muus, R. New Process Solves Nitrate Corrosion. Chem. Eng. 74( 14): 108, July 3, 1967.
5. Ellwood, P. Nitrogen Fertilizer Plant Integrates Dutch and American Know-How. Chem. Eng. p. 136-138,
May 11, 1964.
6. Che nico, Ammonium Nitrate Process Information Sheets.
7. Unpublished source sampling data. Resources Research, Incorporated. Reston. Virginia.
8. Private communication with personnel from Gulf Design Corporation. Lakeland, Florida.
6.8-2
EMISSION FACTORS
2/72
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6.9 ORCHARD HEATERS hy Dennis H Ackcr.son
6.9.1 General1-6
Orchard heaters are commonly used in various areas of the United States to prevent frost damage to hint and
fruit trees. The five common types of orchard heaters—pipeline, lazy flame. leturn stack, cone, and solid fuel are
shown in Figure 6.9-1. The pipeline heater system is operated from a central control and fuel is distributed by a
piping system from a centrally located tank. Lazy flame, return stack, and cone heaters contain mtegial fuel
reservoirs, but can be converted to a pipeline system. Solid fuel heaters usualK consist only of solid briquettes,
which are placed on the ground and ignited.
The ambient temperature at which orchard heaters are lequned is determined primarily by the type of fruit
and stage of maturity, by the daytime temperatures, and by the moisture content of the soil and an.
During a heavy thermal inversion, both convective and radiant heating methods are useful in preventing fiost
damage; there is little difference in the effectiveness of the various heaters. The temperature response for a given
fuel rate is about the same for each type of heater as long as the heater is clean and does not leak. When theie is
little or no thermal inversion, radiant heat provided by pipeline, return stack, or cone heateis is the most effective
method for preventing damage.
Proper location of the heaters is essential to the uniformity of the radiant heat distributed among the trees.
Heaters are usually located in the center space between four trees and are staggered from one row to the next.
Extra heaters are used on the borders of the orchard.
6.9.2 Emissions1'6
Emissions from orchard heaters are dependent on the fuel usage rate and the type of heater. Pipeline heaters
have the lowest particulate emission rates of all orchard heaters. Hydrocarbon emissions are negligible in the
pipeline heaters and in lazy flame, return stack, and cone heaters that have been converted to a pipeline system.
Nearly all of the hydrocarbon losses are evaporative losses from fuel contained in the heater reservoir. Because of
the low burning temperatures used, nitrogen oxide emissions are negligible.
Emission factors for the different types of orchard heaters are presented in Table 6.9-1 and Figure 6.9-2
4/73 Food and Agricultural Industry 6.9-1
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PIPELINE HEATER
LAZY FLAME
CONE STACK
RETURN STACK
SOLID FUEL
Figure 6.9-1. Types of orchard heaters.6
6.9-2
EMISSION FACTORS
4/73
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co
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0)
03
0)
CO
o
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o
CO
CO
LLl
C3
E
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0)
O
CO
0.
CM
CO
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g>
L
'SNOISSIW3
12/75
Food and Agricultural Industry
6.9-3
-------
Table 6.9-1. EMISSION FACTORS FOR ORCHARD HEATERS3
EMISSION FACTOR RATING: C
Pollutant
Participate
Ib/htr-hr
kg/htr-hr
Sulfur oxides
Ib/htr-hr
kg/htr-hr
Carbon monoxide
Ib/htr-hr
kg/htr-hr
Hydrocarbonsf
Ib/htr-yr
kg/htr-yr
Nitrogen oxides'1
Ib/htr-hr
kg/htr-hr
Type of heater
Pipeline
b
b
0.1 3Sd
0.06S
6.2
2.8
Neg9
Neg
Neg
Neg
Lazy
flame
b
b
0.11S
0.05S
NA
NA
16.0
7.3
Neg
Neg
Return
stack
b
b
0.1 4S
0.06S
NA
NA
16.0
7.3
Neg
Neg
Cone
b
b
0.1 4S
0.06S
NA
NA
16.0
7.3
Neg
Neg
Solid
fuel
0.05
0,023
NAe
NA
NA
NA
Neg
Neg
Meg
Meg
References 1, 3, 4, and 6.
"Paniculate emissions for pipeline, lazy flame, return stack, and cone heators are
shown in Figure 6.9-2.
C8ased on emission factors for fuel oil combustion in Section 1.3.
dS=sulfur content.
eNot available.
fBased on emission factors for fuel oil combustion in Section 1.3. Evaporative
losses only. Hydrocarbon emissions from combustion are considered negligible.
Evaporative hydrocarbon losses for units that are part of a pipeline system are
negligible.
Negligible.
hLittle nitrogen oxide is formed because of the relatively low combustion
temperatures.
References for Section 6.9
1. Air Pollution in Ventura County. County of Ventura Health Department, Santa Paula, Calif. June 1966.
2. Frost Protection in Citrus. Agricultural Extension Service, University of California, Ventura. November
1967.
3. Personal communication with Mr. Wesley Snowden. Valentine, Fisher, and Tomlinson, Consulting Engineers,
Seattle, Washington. May 1971.
4. Communication with the Smith Energy Company, Los Angeles, Calif. Jam; - y 1968.
5. Communication with Agricultural Extension Service, University of California, Ventura, Calif. October 1969.
6. Personal communication with Mr. Ted Wakai. Air Pollution Control District, County of Ventura, Ojai, Calif.
May 1972.
6.9-4
EMISSION FACTORS
12/75
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6.10 PHOSPHATE FERTILIZERS
Nearly all phosphatic fertilizers are made from naturally occurring, phosphorus-containing minerals such as
phosphate lock. Because the phosphorus content of these mineials is not in a form that is readily available to
growing plants, the minerals must be treated to conveit the phosphorus to a plant-available form. This conversion
can be done either by the process of acidulation or by a thermal process. The intermediate steps of the mining of
phosphate rock and the manufacture of phosphoric acid are not included in this section as they are discussed in
other sections of this publication: it should be kept in mind, however, that large integrated plants may have all of
these operations taking place at one location.
In this section phosphate fertilizers have been divided into thiee categories. (1) normal superphosphate. (2)
triple superphosphate, and (3) ammonium phosphate. Emission factors for the various processes imolved aie
shown in Table 6.10-1.
Table 6.10-1. EMISSION FACTORS FOR THE PRODUCTION
OF PHOSPHATE FERTILIZERS
EMISSION FACTOR RATING: C
Type of product
Normal superphosphate0
Grinding, drying
Main stack
Triple superphosphate0
Run-of-pile (ROP)
Granular
Diammonium phosphated
Dryer, cooler
Ammoniator-granulator
Particulates3
Ib/ton
9
—
-
_
80
2
kg/MT
4.5
—
-
—
40
1
Fluoridesb
Ib/ton
-
0.15
0.03
0.10
e
0.04
kg/MT
-
0.075
0.015
0.05
e
0.02
aControl efficiencies of 99 percent can be obtained with fabric filters.
bTotal fluorides, including paniculate fluorides. Factors all represent
outlet emissions following control devices, and should be used as typical
only in the absence of specific plant information.
cReferences 1 through 3.
^References 1, 4, and 5 through 8.
Included in ammomator-granulator total.
6. 1 0. 1 Normal Superphosphate
6.10.1.1 General4'9 -Normal superphosphate (also called single or ordinary superphosphate) is the product
resulting from the acidulation of phosphate rock with sulfuric acid. Normal superphosphate contains from 16 to
22 percent phosphoric anhydride (P2^5)- The physical steps involved in making superphosphate are: (1) mixing
rock and acid, (2) allowing the mix to assume a solid form (denning), and (3) storing (curing) the material to
allow the acidulation reaction to be completed. After the curing period, the product can be ground and bagged
for sale, the cured superphosphate can be sold directly as run-of-pile product, or the material can be granulated
for sale as granulated superphosphate.
2/72
Food and Agricultural Industry
6.10-1
-------
6.10.1.2 Emissions — The gases released from the acidulation of phosphate rock contain silicon tetrafluoride,
carbon dioxide, steam, particulates, and sulfur oxides. The sulfur oxide emissions arise from the reaction of
phosphate rock and sulfuric acid.10
If a granulated superphosphate is produced, the vent gases from the granulator-ammoniator may contain
particulates, ammonia, silicon tetrafluoride, hydrofluoric acid, ammonium chloride, and fertilizer dust. Emissions
from the final drying of the granulated product will include gaseous and particulate fluorides, ammonia, and
fertilizer dust.
6. 1 0. 2 Triple Superphosphate
6.10.2.1 General4 -9-Triple superphosphate (also called double or concentrated superphosphate) is the product
resulting from the reaction between phosphate rock and phosphoric acid. The product generally contains 44 to
52 percent ?205, which is about three times the P2®5 usually found in normal superphosphates.
Presently, there are three principal methods of manufacturing triple superphosphate. One of these uses a cone
mixer to produce a pulverized product that is particularly suited to the manufacture of ammoniated fertilizers.
This product can be sold as run-of-pile (ROP), or it can be granulated. The second method produces in a
multi-step process a granulated product that is well suited for direct application as a phosphate fertilizer. The
third method combines the features of quick drying and granulation in a single step.
6.10.2.2 Emissions-Most triple superphosphate is the nongranular type. The exit gases from a plant producing
the nongranular product will contain considerable quantities of silicon tetrafluoride, some hydrogen fluoride, and
a small amount of particulates. Plants of this type also emit fluorides from the curing buildings.
In the cases where ROP triple superphosphate is granulated, one of the greatest problems is the emission of
dust and fumes from the dryer and cooler. Emissions from ROP granulation plants include silicon tetrafluoride,
hydrogen fluoride, ammonia, particulate matter, and ammonium chloride.
In direct granulation plants, wet scrubbers are usually used to remove the silicon tetrafluoride and hydrogen
fluoride generated from the initial contact between the phosphoric acid and the dried rock. Screening stations
and bagging stations are a source of fertilizer dust emissions in this type of process.
6.10.3 AMMONIUM PHOSPHATE
6.10.3.1 General— The two general classes of ammonium phosphates are monammonium phosphate and
diammonium phosphate. The production of these types of phosphate fertilizers is starting to displace the
production of other phosphate fertilizers because the ammonium phosphates have a higher plant food content
and a lower shipping cost per unit weight
There are various processes and process variations in use for manufacturing ammonium phosphates. In general,
phosphoric acid, sulfuric acid, and anhydrous ammonia are allowed to react to produce the desired grade of
ammonium phosphate. Potash salts are added, if desired, and the product is granulated, dried, cooled, screened,
and stored.
6.10-2 EMISSION FACTORS 2/72
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6.10.3.2 Emissions-The major pollutants from ammonium phosphate production are fluoride, particulates, and
ammonia. The largest sources of particulate emissions are the cage mills, where oversized products from the
screens are ground before being recycled to the ammoniator. Vent gases from the ammoniator tanks are the major
source of ammonia. This gas is usually scrubbed with acid, however, to recover the residual ammonia.
References for Section 6.10
1. Unpublished data on phosphate fertilizer plants. U.S. DHEW, PHS, National Air Pollution Control
Administration, Division of Abatement. Durham, N.C. July 1970.
2. Jacob, K. 0., H. L. Marshall, D. S. Reynolds, and T. H. Tremearne. Composition and Piopertics of
, Superphosphate. Ind. Eng. Chem. 54(6).722-728. June 1942.
3. Slack, A. V. Phosphoric Acid, Vol. 1, Part II. New York, Marcel Dekker, Incorporated, i 968. p. 732.
f' 4. Steam, A. (ed.). Air Pollution, Sources of Air Pollution and Their Control, Vol. Ill, 2nd Ed. New York,
Academic Press. 1968. p. 231-234.
5. Teller, A. J. Control of Gaseous Fluoride Emissions. Chem. Eng. Progr. 63(3): 75-79, March 1967.
6. Slack, A. V. Phosphoric Acid, Vol. I, Part II. New York, Marcel Dekker, Incorporated. 1968. p. 722.
7. Slack, A. V. Phosphoric Acid, Vol. 1, Part II. New York, Marcel Deklcer, Incorporated. 1968. p. 760-762.
8. Salee, G. Unpublished data from industrial source. Midwest Research Institute. June 1970.
9. Bixby, D. W. Phosphatic Fertih/er's Properties and Processes. The Sulphur Institute. Washington, D.C.
October 1966.
10. Sherwm, K. A. Transcript of Institute of Chemical Engineers, London. 32 172. 1954.
2/72 Food and Agricultural Industry 6.10-3
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6.11 STARCH MANUFACTURING
6.11.1 Process Description1
The basic raw material in the manufacture of starch is dent corn, which contains starch. The starch in the
corn is separated from the other components by "wet milling."
The shelled grain is prepared for milling in cleaners that remove both the light chaff and any heavier foreign
material. The cleaned corn is then softened by soaking (steeping) it in warm water acidified with sulfur dioxide.
The softened corn goes through attrition mills that tear the kernels apart, freeing the germ and loosening the hull.
The remaining mixture of starch, gluten, and hulls is finely giound. and the coarser fiber particles are removed by
' screening. The mixture of starch and gluten is then separated by centrifuges, after which the starch is filtered and
washed. At this point it is dried and packaged for market.
«
' 6.11.2 Emissions
ft
1 The manufacture of starch from corn can result in significant dust emissions. The various cleaning, grinding.
and screening operations are the major sources of dust emissions. Table 6.11-1 presents emission factors for starch
manufacturing.
Table 6.11-1. EMISSION FACTORS
FOR STARCH MANUFACTURING3
EMISSION FACTOR RATING: D
Type of operation
Uncontrolled
Controlled13
Particulates
Ib/ton
8
0.02
kg/MT
4
0.01
aReference 2.
°Based on centrifugal gas scrubber.
References for Section 6.11
1. Starch Manufacturing. In: Kirk-Othmer Encyclopedia of Chemical Technology, Vol. IX. New York, John
Wiley and Sons, Inc. 1964.
2. Storch, H. L. Product Losses Cut with a Centrifugal Gas Scrubber. Chem. Eng. Progr. 62:51-54. April 1966.
2/72 Food and Agricultural Industry 6.11-1
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I
6 12 SUGAR CANE PROCESSING revised by Tom Lahre
>
6.12.1 General l'3
Sugar cane is burned in the field prior to harvesting to remove unwanted foliage as well as to control rodents
and insects. Harvesting is done by hand or, where possible, by mechanical means.
After harvesting, the cane goes through a series of processing steps for conversion to the final sugar product. It
is first washed to remove dirt and trash; then crushed and shredded to reduce the size of the stalks. The juice is
next extracted by one of two methods, milling or diffusion. In milling, the cane is pressed between heavy rollers
to squeeze out the juice; in diffusion, the sugar is leached out by water and thin juices. The raw sugar then goes
through a series of operations including clarification, evaporation, and crystallization in order to produce the final
product. The fibrous residue remaining after sugar extraction is called bagasse.
All mills fire some or all of their bagasse in boilers to provide power necessary in their milling operation. Some,
having more bagasse than can be utilized internally, sell the remainder for use in the manufacture of various
chemicals such as furfural.
6.12.2 Emissions 2>3
The largest sources of emissions from sugar cane processing are the openfield burning in the harvesting of the
crop and the burning of bagasse as fuel. In the various processes of crushing, evaporation, and crystallization,
relatively small quantities of particulates are emitted. Emission factors for sugar cane field burning are shown in
Table 2.4-2. Emission factors for bagasse firing in boilers will be included in Chapter 1 in a future supplement.
References for Section 6.12
1. Sugar Cane. In: Kirk-Othmer Encyclopedia of Chemical Technology, Vol. IX. New York, John Wiley and
Sons, Inc. 1964.
2. Barley, E. F. Air Pollution Emissions from Burning Sugar Cane and Pineapple from Hawaii. In: Air Pollution
from Forest and Agricultural Burning. Statewide Air Pollution Research Center, University of California,
Riverside, Calif. Prepared for Environmental Protection Agency, Research Triangle Park, N.C. under Grant
No. R80071 I.August 1974.
3. Background Information for Establishment of National Standards of Performance for New Sources. Raw Cane
Sugar Industry. Environmental Engineering, Inc. Gainesville, Fla. Prepared for Environmental Protection
Agency, Research Triangle Park, N.C. under Contract No. CPA 70-142, Task Order 9c. July 15, 1971.
4/76 Food and Agricultural Industry 6.12-1
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References for Section 6.12
1. Sugar Cane. In: Kirk-Othmer Encyclopedia of Chemical Technology, Vol. IX. New York, John Wiley and
Sons, Inc. 1964.
2. Cooper, J. Unpublished data on emissions from the sugar cane industry. Air Pollution Control Agency, Palm
Beach County, Florida. July 1969.
I
6.12-2 EMISSION FACTORS 2/72
* U.S. GOVERNMENT PRINTING OFFICE: 1977—740-104/409 Region No. 4
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